The first stage of the F6 motorway extension will take up to 2000 trucks off the road each day between Arncliffe and Kogarah, the state government says.
Reduced traffic congestion on Princes Highway and The Grand Parade, and an improved “amenity of the foreshore precinct at Brighton-Le-Sands” are other touted benefits.
Premier Gladys Berejiklian announced last week the first stage of the motorway would be four kilometre long twin tunnels from the WestConnex New M5 junction at Arncliffe to President Avenue, Kogarah.
The tunnels will be 75 metres underground, with a provision for a future extension south.
Investigations will continue for stage two from Kogarah to Loftus, while the proposed third section through Royal National Park to Waterfall has been abandoned.
Ms Berejiklian said a further $35 million, on top of $15 million allocated in the state budget, would be spent planning and project development for the first section.
“At this point a final design for the tunnel has not been decided, as we will take our time to listen to the community before coming back in mid-2018 with a detailed design and cost for the project,” she said.
Roads Minister Melinda Pavey said the government wanted tunnel excavation and other construction work for the first stage to begin in early 2019.
Ms Pavey said the impact on properties was expected to be low, compared to other major road projects.
“Ten homes will be impacted and Roads and Maritime Services already owns five of them,” she said.
Labor's infrastructure spokesman, Michael Daley, said the government needed to release the business case and options considered before committing to the project.
"They have already made their mind up about what they are going to do and not a single community member along the route has been consulted about it at all," he said.
The government said the new motorway would bypass up to 23 sets of traffic lights on the Princes Highway between St Peters and Kogarah.
Motorists would get better access to the Sydney motorway network while traffic to and from the northern suburbs would avoid congestion around the airport.
The government said disruption to the community would be minimised by the motorway being built in a tunnel.
Forecast average travel time savings from stage one would be:
- Kogarah to the City, about five minutes.
- Taren Point to Mascot, about 10 minutes.
- Kogarah to South Sydney, about 10 minutes.
Community information sessions: rms.nsw.gov.au/f6