A disused railway tunnel to Sydney's station for the dead could be given new life transporting pedestrians and cyclists to Redfern.

An underground track to Mortuary Station on Regent Street has been flagged as a possible extension to the Goods Line, a former freight corridor between Central and Pyrmont that is being redeveloped as a civic ''spine'' to connect the city to Darling Harbour.

Now and then: Mortuary Station.

The 800-metre tunnel under Railway Square emerges behind the ABC studios in Ultimo, where it meets a section of track that was converted into a walkway in 2002.

A Transport for NSW report said a feasibility study would consider whether the abandoned tunnel could be redeveloped for pedestrian and bicycle access.