Homes evacuated as inner west factory blaze closes Princes Highway

Fire crews spent the night battling a factory fire in Sydney's inner west, forcing the evacuation of nearby residents and the closure of a major road.

The building in St Peters was engulfed in flames by the time emergency services arrived just after 11pm on Friday.

Homes nearby were cleared as a precaution. No injuries have been reported.

The fire is not thought to be suspicious, NSW Police say.

All northbound lanes on the Princes Highway at St Peters remain closed.

AAP