Man, 50, dies after Sydney building fire

A 50-year-old man has died in hospital after a fire tore through his home in Sydney's inner west.

Emergency services were called to the blaze at a duplex on Stanley Street in Putney shortly before 4am on Saturday, which forced the evacuation of surrounding residents, police said.

The man, believed to be the only person who lived in the building, was taken to nearby Concord Hospital in a critical condition but later died.

One firefighter was treated for exhaustion while three neighbours were taken to hospital for observation after smoke inhalation.

The cause of the fire is not yet known but a crime scene has been established ahead of a forensic examination.