Mount Ousley Interchange project looking east towards Mount Ousley Road in October 2025. Photo: TfNSW.
The foundations for the new Mt Ousley Interchange are starting to take shape despite unprecedented rainfall throughout the project’s first full year.
According to Transport for NSW’s December community newsletter, more than 275,000 hours have been put in by workers to ensure the major infrastructure project – now 34 per cent complete – remains on track.
More than 35,000 tonnes of earthwork material was placed and 1033 cubes of concrete poured as part of the major works on the Interchange in 2025, with the transformation set to continue with key traffic changes and milestones expected to be met in 2026.
The weather created an extra challenge for the project progression, with the region recording 124 per cent above the average annual rainfall amount. It delayed some planned nightworks, but didn’t stop the completion of key aspects such as major utility relocation along the M1 Princes Motorway and the upgrades and extension to the pedestrian bridge over the motorway at Northfields Avenue.
Eighteen per cent of the total earthworks have now been placed with 20 per cent of the foundation treatment work completed, 10 per cent of stormwater drainage laid and progress seen through the drilling and pouring of 59 piles for the bridges over the M1.
The significant work already made on Interchange bridges and heavy vehicle safety ramps are set to be even more crucial in the next year.
Once the new heavy vehicle safety ramp opens and the existing ramp closes, TfNSW will start work on the new heavy vehicle off ramp. Work will also continue on the new bridge over the heavy vehicle bypass.
In late 2026 the first major traffic change will occur at the intersection of Mt Ousley Road and the M1, when southbound motorway traffic currently turning left onto Mount Ousley Road to access North Wollongong and Wollongong will temporarily use the new heavy vehicle off ramp.
After these changes, the new southbound heavy vehicle bypass will be built and the bypass lane will be lowered by around three and a half metres from the existing level of Mt Ousley Road.
The transformation is already being realised on the surface with images of work from the year seen through the Transport for NSW photobook.
Construction will return in full swing from 5 January 2026, following a short closure over the new year, with night works scheduled in addition to the standard schedule to minimise disruptions and improve the safety of workers.
In coming weeks, residents can expect extensive excavation and ground stabilisation work as well as the construction of supports for the bridge, the installation of road kerbing, barriers and guardrails, drainage and landscaping preparation, the relocation and installation of utilities, concrete pours, pavement work and line marking.
The project looking north along the M1 in October 2025. Photo: TfNSW.
Construction activities will also take place for the noise wall on Dumfries Avenue and on future road bridges over the M1.
More truck movements are expected with the transportation of soil and material between work sites, as well as the delivery of oversized equipment.
Work hours for the project are Monday to Friday between 7 am and 6 pm and Saturday between 8 am and 1 pm, but there will also be some work Monday to Thursdays between 7 pm and 6 am.
This bout of night works is expected to be completed by Thursday 29 January 2026, depending on weather.
And there are more big things to come over the next 12 months.
From February, there will be four weekends over a six-month period where work will take place continuously from 6 am Saturday until 4 am Monday on Mt Ousley Road and the M1.
During this work a full closure of Mt Ousley Road between Gaynor Avenue and the M1 will occur with detours in place.
This will allow for workers to increase the height of Mount Ousley Road, build new road pavement between Gaynor Avenue and the motorway, build part of the new intersection at Mt Ousley Road and the motorway and progress work on the new southbound access road to University Avenue.
Updates on the project and closures are available through the Transport for NSW website.
