Sydney's most controversial harbourside apartment block could be given a new lease of life with supporters calling for socially-minded developers to purchase the brutalist Sirius building for a mix of social and affordable housing.

The NSW government wants to sell the site – which has been used for social housing for more than 30 years – to developers who’d knock down the building and replace it with hundreds of private apartments. But community group Save Our Sirius says its proposal could see the original…