Police say Balmain unit fire 'suspicious'

Police investigating a fire at a unit in Sydney's inner west say it is being treated as suspicious.

A major blaze at a car wrecking business in Adelaide's north has been contained. (AAP)

Police say a fire that ripped through a unit in Sydney's inner west is being treated as suspicious.

Emergency services were called to the unit block on Nicholson Street, Balmain East just after 10pm on Friday to find it well alight.

Residents were evacuated for their safety while the blaze was extinguished, but were allowed back inside a short time later when the area was deemed safe.

No one was injured and the neighbouring units were unaffected.

Detectives and forensic specialists remain at the scene with the blaze being treated as suspicious.