Pru Goward has "driven past" the landmark Sirius building at the Rocks for 35 years but the NSW social housing minister only relatively recently got to take a look inside.

"My breath was taken away by the incredible views," she said.

Those sweeping views, taking in the Sydney Harbour Bridge and the Opera House, are what the NSW government hopes will deliver revenue of $100 million, or possibly more, from a developer when Sirius - home to public housing tenants since 1980 - officially goes on sale on Thursday.

Ms Goward's controversial announcement three years ago that Sirius would be sold - with the proceeds used to build new social housing - has been met with fierce opposition from tenants, community members, architects, the Labor opposition and Sydney Lord Mayor Clover Moore.