Barangaroo Station, which will begin trial runs of trains in 2023 and will be open for commuters in 2024, is set to connect 31 kilometres of railway line from Chatswood in the city's north, to Sydenham in the inner west.

Excavation on the station was carried out for three years, with more than 650,000 tonnes of crushed rock removed from the site.

Mr Perrottet walked the tracks of the "transformative" station.

"This incredible city-shaping project is coming together before our eyes,” he said.

"Sydney Metro will transform the way we travel around our great city — the trip deep under Sydney Harbour will take just three minutes between the new Barangaroo Station and Victoria Cross Station at North Sydney." 

  

The station is on track to be completed after two years of construction. (Supplied: NSW Metro)Mr Perrottet said that despite the two-week construction ban during the COVID-19 lockdown the project was on schedule.

"We've made mistakes over the last 18 months, but look at the position we're in.

"The decision to close construction (during the lockdown) was a hard and challenging discussion and debate we had. It was pretty well known that I didn't agree with that decision. 

"But that's part and parcel of trying to make decisions during a pandemic ... and in a pandemic, there is no rulebook."

The $217 million construction contract for the station was awarded to Brisbane-based company BESIX Watpac as part of the $11.5 billion Metro City & Southwest project.

Trackwork has been completed at Barangaroo Metro station ahead of opening in 2024. (Supplied: NSW Metro)Minister for Transport Rob Stokes praised the construction team for completing the tunnels under Sydney Harbour.

"Workers have laid 2,400 railway sleepers and 4,200 tonnes of concrete have been installed to finish this historic railway tunnel under Sydney Harbour," Mr Stokes said.

Sydney Metro site engineer Julie Tran said there had been many "technical difficulties".

"This is only the second metro in Australia so there are definitely new challenges," Ms Tran said.

"It's all coming together, a couple of years ago it was just a hole and dirt.

"I'll tell my children about working on this. It's not just for this generation, but generations after."

The Barangaroo Metro tunnel runs under Sydney Harbour.(Supplied: NSW Metro)New stations are being built in Crows Nest, Victoria Cross, Martin Place, Pitt Street, and Waterloo to connect the rail lines. 

The new station at Barangaroo is now ready for platforms, lifts and escalators to be installed.

The project was launched in 2018, with the first drilling beginning in Marrickville.