The proposed motorway,part of the $16.8 billion WestConnex project,has been hugely controversial in the inner west areas under which it will run.
NSW Planning received submissions from 4480 people and organisations in response to the project,many of them highly critical.
The motorway is to be one of four sections of the 33-kilometre WestConnex project.
The others included a widened M4 between Parramatta and Homebush,which will re-impose a toll on that section;a new tunnel between Beverly Hills and St Peters to be built by 2019;and a tunnel between St Peters and Haberfield,including outlets at Rozelle and Camperdown.
The projects are being funded by the NSW and federal governments,as well as from toll revenue.
"I don't want motorists to lose any more time sitting in the car park that is Parramatta Road,and WestConnex will be crucial in fixing the problem,"said Roads Minister Duncan Gay.
The Federal Minister for Major Projects,Paul Fletcher,said construction was due to start in the middle of the year.
"This is another WestConnex milestone and,once finished,the tunnel will allow motorists to travel between Homebush and Haberfield without stopping at a single traffic light,"Mr Fletcher said.
But Labor's Member for Summer Hill,Jo Haylen,said the government should be scrapping WestConnex,not approving it.
"I'm disappointed the government has decided to move ahead with their plan to rip a hole through the inner west,offering small concessions but more or less sticking with their destructive plan,"Ms Haylen said.
"Despite the consultation emphatically saying the community doesn't want this road,it's business as usual for the government,"she said.
Pauline Lockie,a spokeswoman for the WestCONnex Action Group,which is opposed to the project,said the process had been a"sham",
"We can't trust that those conditions will be met,"Ms Lockie said.
She said the modelling for the project,including its impact on air quality,health,noise and vibration,was based on the provision of two dedicated bus lanes,which may never be built.
Labor's Jodi McKay,the Member for Strathfield,said the surface transport option should be a light rail line from Strathfield to Sydney University,connecting to the existing light rail line at Taverners Hill.
The government has already committed to a light rail line from Parramatta to Strathfield via Sydney Olympic Park.
Ms Haylen said light rail would have multiple advantages over bus lanes. It would carry more people,and better encourage local retail and cafe strips.
"And it could interchange with the existing light rail to give an east-west and north-south connection that we don't have with heavy rail in the area."