A nursing home expansion proposed in one of Melbourne's most desirable pockets, to be built for some of society's most vulnerable, has been blocked by Greens and socialist councillors at the behest of scores of residents.

Clifton Hill's Sambell Lodge is an aged care centre for the disadvantaged, run by the Brotherhood of St Laurence.

Sambell Lodge resident Graeme Doyle in his room, surrounded by his artwork. Credit:Wayne Taylor

Half of its residents were homeless before finding a place, and many have histories of mental illness and alcohol abuse.

The centre's rooms are small and do not have their own bathrooms, and the Brotherhood wants to more than double the size of the 38-year-old centre opposite the Darling Gardens.