We’re building a new bridge on Mill Flat Road, Coatesville

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Update - 16 Dec 2025

Here is what you need to know about how the site will operate over the Christmas holiday and into 2026.

Where

  • Mill Flat Road Bridge, near 6 Mill Flat Road (see location map below)

When

  • From Friday 19 December 2025 to mid-late January 2026

What we’re doing

Christmas Holiday:

  • Works will be paused over the Christmas holiday period. from Friday 19 December 2025 to Monday 5 January 2026. The site area will be made safe for continued unattended use.

Mid-late January 2026:

  • · Removal of the existing temporary bailey bridge

How it may impact you

Christmas Holiday:

The current intersection layout (traffic lights for a 3-way stop/go) will be remaining in place. Light vehicles will have full use of the intersection, however large vehicles will have restricted turning – please refer below text and maps for more information:

  • Coatesville – Riverhead Highway and Mill Flat Road Bridge:
    The current single-lane traffic light setup on Coatesville-Riverhead Highway and Mill Flat Road Bridge will continue.
  • Exiting Mill Flat Road:
    Large vehicles can only turn right (southbound) onto Coatesville-Riverhead Highway. Left-turns will be available for light vehicles only.
  • Entering Mill Flat Road:
    Northbound vehicles on Coatesville-Riverhead Highway can turn left into Mill Flat Road.

Only light southbound vehicles can turn right into Mill Flat Road. Large southbound vehicles cannot turn right, and will need to follow the detour.

Mid-late January 2026 – Bailey Bridge Removal:

  • · Further road closures are require, to remove the Bailey Bridge.
  • · Property access will managed for residents
  • · Detours will be in place while the closures occur, and for more updates please visit AT website via the QR code below
  • · Further details will be shared closer to the closure dates



Update - 15 Oct 2025

Girder installation was successful, with the bridge beams and precast panels to be installed shortly afterwards.


Update - 29 Sept 2025

Construction on the bridge rebuild continues, with JFC completing Stage 1 of the precast panels and preparing for the installation of steel girders. Concrete works on the return wall are scheduled soon, and coating of girders is underway off-site (Photos on this webpage shows girders near completion).

To support these works, a 24/7 lane closure remains in place on Coatesville-Riverhead Highway. We have arranged traffic management changes for upcoming closures (overnight closures and layout changes during the day), including details on the steel girder and precast panel installation updates.

A letter is being distributed to advise residents of expected dates and impacts (noted above on this website). We thank the community for their continued support and patience as we deliver this important infrastructure rebuild.


About the Project

On the afternoon of Friday 27 January 2023 (Auckland Anniversary Weekend) the bridge was washed away during a significant flood event. In addition to the bridge structure being washed away, the following damage also included the Eastern abutment wingwall was washed away, and experienced a scour with exposed abutment beam piles, and the Western abutment experienced some damage.

Post-event, temporary access was established through a forestry track, and a temporary Bailey Bridge was constructed within six days in the same location and opened to the public on the afternoon of Monday February 6, 2023.

Auckland Transport undertook a long-term rebuild of the bridge destroyed in the January 2023 floods, with a new two-lane bridge designed to withstand future extreme weather events. Construction began in April 2025 and is progressing steadily, with traffic maintained via a single lane and completion expected within 12–16 months.

With our contractor JFC, we will need to establish road closures and traffic management layout changes while equipment and bridge structures are delivered to the construction site. A crane will be positioned on the northwestern corner of the Mill Flat Road and Coatesville-Riverhead Highway intersection.


The work we’ll be doing and traffic management & detours

  • Coatesville – Riverhead Highway and Mill Flat Road Bridge
    • The current single-lane traffic light on Coatesville-Riverhead Highway and Mill Flat Road Bridge will continue outside of working hours. During working hours, Traffic Controllers will be in place to assist safe operations through the intersection.
  • Exiting Mill Flat Road:
    • Vehicles can only turn right (southbound) onto Coatesville-Riverhead Highway. Left turns will not be available.
  • Entering Mill Flat Road:
    • Northbound vehicles on Coatesville-Riverhead Highway can still turn left into Mill Flat Road. Right turns into Mill Flat Road will not be available.
  • We’ll try to start the work on time but factors outside our control, such as weather could mean a delayed timeline. If the delay is significant, we’ll notify you and update this webpage regularly.
  • Take care while driving, walking, or cycling in the area. Follow all traffic signs, signals, and directions for safety.
  • We will personally liaise with effected residents to minimise any disruption. Traffic controllers will be on site to assist during these closures.
  • Construction will run between Day and Night shifts to finish as quickly as possible. We know our work can be a bit loud, and that noise – particularly at night – can be disruptive. We’ll try to keep noise levels down.


Benefits to the Community

  • Improved Traffic Flow: The new bridge will help manage the increased traffic volume, reducing delays and congestion.
  • Enhanced Safety: The project will address safety concerns by making it easier for drivers, buses, and heavy vehicles to find safe gaps in traffic, reducing the risk of accidents.
  • Future-Proofing: By accommodating the expected growth in vehicle numbers due to nearby planned housing developments, the intersection will be better prepared for future demands.
  • Reliable Bus Services: The intersection improvements will ensure that bus services remain reliable and efficient, benefiting public transport users.
  • Community-Driven: The project reflects on the feedback and priorities of local residents, ensuring that the upgrades meet the community's needs.
  • Optimal Use of Funding: The plan makes the best use of the available Local Board Transport Capital Fund, ensuring that the investment delivers maximum benefits.


Where we’ll be working

Before the work starts, a work notice letter (attached in important documents on this webpage) will be delivered to affected residents to inform the community about the disruption, lane closures and detours on surrounding roads.

We appreciate your patience during this work. Please follow detour signs when installed at the site.


How to contact us

Our team will be on-site to keep things running smoothly. If you have any queries or concerns about this project, please contact AT:

Email: ATengagement@at.govt.nz (include reference Mill Flat Road Bridge)

Phone: 09 930 5090

If you have any queries related to the construction, please contact contractor JFC Ltd

Contract Manager: Richard Docherty

Project Manager: Bernardo Lamela

Email: MillFlatBridge@jfcltd.co.nz

Phone: 021 420 189 / 021 420 612

Update - 16 Dec 2025

Here is what you need to know about how the site will operate over the Christmas holiday and into 2026.

Where

  • Mill Flat Road Bridge, near 6 Mill Flat Road (see location map below)

When

  • From Friday 19 December 2025 to mid-late January 2026

What we’re doing

Christmas Holiday:

  • Works will be paused over the Christmas holiday period. from Friday 19 December 2025 to Monday 5 January 2026. The site area will be made safe for continued unattended use.

Mid-late January 2026:

  • · Removal of the existing temporary bailey bridge

How it may impact you

Christmas Holiday:

The current intersection layout (traffic lights for a 3-way stop/go) will be remaining in place. Light vehicles will have full use of the intersection, however large vehicles will have restricted turning – please refer below text and maps for more information:

  • Coatesville – Riverhead Highway and Mill Flat Road Bridge:
    The current single-lane traffic light setup on Coatesville-Riverhead Highway and Mill Flat Road Bridge will continue.
  • Exiting Mill Flat Road:
    Large vehicles can only turn right (southbound) onto Coatesville-Riverhead Highway. Left-turns will be available for light vehicles only.
  • Entering Mill Flat Road:
    Northbound vehicles on Coatesville-Riverhead Highway can turn left into Mill Flat Road.

Only light southbound vehicles can turn right into Mill Flat Road. Large southbound vehicles cannot turn right, and will need to follow the detour.

Mid-late January 2026 – Bailey Bridge Removal:

  • · Further road closures are require, to remove the Bailey Bridge.
  • · Property access will managed for residents
  • · Detours will be in place while the closures occur, and for more updates please visit AT website via the QR code below
  • · Further details will be shared closer to the closure dates



Update - 15 Oct 2025

Girder installation was successful, with the bridge beams and precast panels to be installed shortly afterwards.


Update - 29 Sept 2025

Construction on the bridge rebuild continues, with JFC completing Stage 1 of the precast panels and preparing for the installation of steel girders. Concrete works on the return wall are scheduled soon, and coating of girders is underway off-site (Photos on this webpage shows girders near completion).

To support these works, a 24/7 lane closure remains in place on Coatesville-Riverhead Highway. We have arranged traffic management changes for upcoming closures (overnight closures and layout changes during the day), including details on the steel girder and precast panel installation updates.

A letter is being distributed to advise residents of expected dates and impacts (noted above on this website). We thank the community for their continued support and patience as we deliver this important infrastructure rebuild.


About the Project

On the afternoon of Friday 27 January 2023 (Auckland Anniversary Weekend) the bridge was washed away during a significant flood event. In addition to the bridge structure being washed away, the following damage also included the Eastern abutment wingwall was washed away, and experienced a scour with exposed abutment beam piles, and the Western abutment experienced some damage.

Post-event, temporary access was established through a forestry track, and a temporary Bailey Bridge was constructed within six days in the same location and opened to the public on the afternoon of Monday February 6, 2023.

Auckland Transport undertook a long-term rebuild of the bridge destroyed in the January 2023 floods, with a new two-lane bridge designed to withstand future extreme weather events. Construction began in April 2025 and is progressing steadily, with traffic maintained via a single lane and completion expected within 12–16 months.

With our contractor JFC, we will need to establish road closures and traffic management layout changes while equipment and bridge structures are delivered to the construction site. A crane will be positioned on the northwestern corner of the Mill Flat Road and Coatesville-Riverhead Highway intersection.


The work we’ll be doing and traffic management & detours

  • Coatesville – Riverhead Highway and Mill Flat Road Bridge
    • The current single-lane traffic light on Coatesville-Riverhead Highway and Mill Flat Road Bridge will continue outside of working hours. During working hours, Traffic Controllers will be in place to assist safe operations through the intersection.
  • Exiting Mill Flat Road:
    • Vehicles can only turn right (southbound) onto Coatesville-Riverhead Highway. Left turns will not be available.
  • Entering Mill Flat Road:
    • Northbound vehicles on Coatesville-Riverhead Highway can still turn left into Mill Flat Road. Right turns into Mill Flat Road will not be available.
  • We’ll try to start the work on time but factors outside our control, such as weather could mean a delayed timeline. If the delay is significant, we’ll notify you and update this webpage regularly.
  • Take care while driving, walking, or cycling in the area. Follow all traffic signs, signals, and directions for safety.
  • We will personally liaise with effected residents to minimise any disruption. Traffic controllers will be on site to assist during these closures.
  • Construction will run between Day and Night shifts to finish as quickly as possible. We know our work can be a bit loud, and that noise – particularly at night – can be disruptive. We’ll try to keep noise levels down.


Benefits to the Community

  • Improved Traffic Flow: The new bridge will help manage the increased traffic volume, reducing delays and congestion.
  • Enhanced Safety: The project will address safety concerns by making it easier for drivers, buses, and heavy vehicles to find safe gaps in traffic, reducing the risk of accidents.
  • Future-Proofing: By accommodating the expected growth in vehicle numbers due to nearby planned housing developments, the intersection will be better prepared for future demands.
  • Reliable Bus Services: The intersection improvements will ensure that bus services remain reliable and efficient, benefiting public transport users.
  • Community-Driven: The project reflects on the feedback and priorities of local residents, ensuring that the upgrades meet the community's needs.
  • Optimal Use of Funding: The plan makes the best use of the available Local Board Transport Capital Fund, ensuring that the investment delivers maximum benefits.


Where we’ll be working

Before the work starts, a work notice letter (attached in important documents on this webpage) will be delivered to affected residents to inform the community about the disruption, lane closures and detours on surrounding roads.

We appreciate your patience during this work. Please follow detour signs when installed at the site.


How to contact us

Our team will be on-site to keep things running smoothly. If you have any queries or concerns about this project, please contact AT:

Email: ATengagement@at.govt.nz (include reference Mill Flat Road Bridge)

Phone: 09 930 5090

If you have any queries related to the construction, please contact contractor JFC Ltd

Contract Manager: Richard Docherty

Project Manager: Bernardo Lamela

Email: MillFlatBridge@jfcltd.co.nz

Phone: 021 420 189 / 021 420 612

Page last updated: 16 Dec 2025, 12:46 PM