Abandoned tunnels under the city of Sydney, Australia are to be turned into a new heritage attraction under plans outlined by the New South Wales (NSW) government.

Originally intended as a transport link between two suburban areas – the Eastern Suburbs and the Northern Beaches – the tunnels, which sit underneath the city centre’s St James station, were dug out in the 1920s but the plans to turn them into a transit link were stymied by the Great Depression of the 1930s. The tunnels where used as air raid shelters during World War 2.

The NSW government is now calling for expressions of interest to turn them into a "world-class" attraction. No concrete plans are in place as to what the attraction would actually be.

"Around the world, hidden spaces are being converted into unique experiences and we want St James Station to be part of that," said NSW transport and infrastructure minister Andrew Constance.

"That’s why we’re casting the net right across the world. We want the world’s best to come up with the best ideas."

St James Station was the first underground station in Australia and is still operational. It is heritage listed as a place of state significance.

The process of expressions of interest is being managed by Sydney Trains and estate agent CBRE. It opened on 27 September 2018 and will close on 6 November 2018.