A new tunnel under Sydney Harbour which links the city's inner west to the lower north shore has received NSW planning approval.
The Western Harbour Tunnel and Warringah Freeway Upgrade will include a 6.5km tunnel stretching from Rozelle to North Sydney's Warringah Freeway.
Transport Minister Andrew Constance said the tunnel - construction for which is likely to start before April - will cut travel time from the inner west to the north shore by up to 20 minutes.
"The Western Harbour Tunnel will take pressure off the Sydney Harbour Bridge, Sydney Harbour Tunnel, Anzac Bridge and Western Distributor corridors to revolutionise transport capacity in and around our city," Mr Constance said in a statement.
The tunnel is planned to connect to the Beaches Link, a 7km tunnel linking the lower north shore to Frenchs Forest on the northern beaches.
That project is still in the public consultation phase.
Both tunnels - not expected to open for at least another four years - will be tolled.
NSW Opposition Leader Jodi McKay on Friday urged the government to learn from its "mistakes" with the Westconnex M8 Tunnel.
She said communities along the route were treated with disrespect, and there was a lack of transparency about the project's cost.
The Westconnex Tunnel ended up draining $18 billion from state coffers - almost double the original estimate - while the cost of this project has not even been disclosed, she said.
"Let's be transparent. Let's be honest. Let's not stuff around the communities that are going to be impacted by this road," Ms McKay said.
"Tell us up front how much this project is going to cost, and how it's going to be funded."
Australian Associated Press