Sydney will be hit with more traffic chaos over the coming months as buildings are torn down to make way for the new Sydney Metro rail link.
The new underground train line, which will link Chatswood on the north shore through the CBD to Sydenham in the inner west, was given the green light on Tuesday, with construction to begin later in the year.
"We've made no secret of the fact we're going to disrupt people's lives very heavily in the next 24 months," NSW Transport Minister Andrew Constance said.
"Given the buildings which will need to come down in town, there is going to be additional truck movement to be able to deal with that."
City residents and retailers already dealing with the havoc of light rail construction along George Street will face further congestion as several buildings around Martin Place and Pitt Street are demolished to make way for the rail link.
It will eventually extend above-ground from Sydenham to Bankstown, with the whole rail line to connect to the northwest line, now under construction.
The entire metro line will eventually run 66km from Rouse Hill to Bankstown, via Chatswood and the CBD.
"Tomorrow's Sydney is going to deliver a metro train which will transform communities, transform lives and transform the way in which people move in and around Sydney," Mr Constance said.
"Tens of thousands of Sydneysiders every day are going to catch the new supertrain."
Shadow Planning Minister Michael Daley has raised doubts about the cost efficiency of the project, which is expected to come to between $11.5-12.5 billion.
"The Baird government does not have a very good track record of procuring and delivering infrastructure that is value for money and delivered fully and transparently," he said on Tuesday, refererring to the budget blowouts on Westconnex and the city light rail.
The driverless trains are expected to double the capacity, with the number of passengers able to travel to and from the city per hour jumping from 23,000 to 46,000.
The network will also dispense with timetables and instead run trains every two minutes each way through the CBD and every four minutes along the northwest line during peak hours.
While the northwest link, from Rouse Hill to Chatswood, is expected to be completed in the first half of 2019, the CBD and southwest stations are not scheduled to open until 2024.