Plans to build a tunnel in the Rocky Mountains of New South Wales have moved forward with the award of a contract for the environmental assessment.

Deputy premier and minister for regional NSW John Barilaro said Aecom Australia had been selected in a competitive tender process to work on the proposed 11km tunnel, a central component of the Great Western Highway upgrade between Katoomba and Lithgow. It is set to be Australia’s longest road tunnel.

“This project will transform journeys between the Central West and the East Coast, delivering a safe and more efficient journey for locals, truckies and tourists,” said Barilaro.

“Aecom Australia are industry leaders in their field and bring extensive, demonstrated experience in the environmental assessment of roads and tunnels, having worked on major infrastructure projects, including NorthConnex and the M6 Stage 1.

“They have also demonstrated a comprehensive understanding of the unique and sensitive Blue Mountains environment and will be working to develop rigorous measures to avoid and mitigate impacts from the tunnel work.”

Minister for regional transport and roads Paul Toole said the tunnel would be a game-changer for all motorists driving between Western NSW and Sydney. “Aecom Australia will now need to ensure that the project includes appropriate measures to protect the Blue Mountains’ natural heritage,” he said. “This critical work will focus on continuing the detailed environmental investigations to confirm the feasibility of a tunnel in this location, and will provide the basis for the environmental impact statement, due for extensive community consultation next year.

“Similar contracts have already been awarded for the east and west sections of the upgrade, so it’s great to see the central section reach that stage too.”

“We’re confident that the assessment will show the feasibility of this ambitious project and that we can build an Australian first right here in the Blue Mountains.”

The AU$4.5bn duplication of the Great Western Highway between Katoomba and Lithgow is jointly funded by the Australian and NSW Governments. Construction work is scheduled to start in late 2022, with the tunnel slated to begin construction in 2024.