A never before seen view of a Sydney landmark has been uncovered as part of work on one of Australia’s biggest construction projects.

Works to dig a 19-meter escalator tunnel to create one of the entrances to the new Martin Place metro station are now complete.

The works have exposed a view of Sydney Tower and the MLC Centre from 19 meters under Martin Place.

The tunnelling is part of the $11.5-$12.5 billion Sydney Metro Project which will deliver 31 stations and more than 66 kilometres of new rail line by 2024 and will see customers turn up and go without requiring a timetable.

The new tunnel will house four escalators as customers travel to the new underground metro station.

The tunnel was built under the historic 50 Martin Place building, navigating the basement of the heritage-listed structure.

Its excavation took seven weeks and saw removal of around 2,000 tonnes of crushed rock along with the use of 700 tonnes of shotcrete for lining.

It is now being waterproofed and lined with concrete.

Work on the new station (image: supplied)

NSW Transport Minister Andrew Constance said the milestone along with the exposed view serve as a reminder of project progress.

“We’re getting on with the job of delivering Sydney Metro through the city as quickly as possible,” Constance said.

“This completed entrance tunnel is a visible reminder that a new generation of fast, safe and reliable driverless metro trains are on their way to more of Sydney.”