Sixteen elderly people have been forced to leave their Port Melbourne building overnight after four fires were deliberately lit inside.
MFB spokesman Trevor Woodward said four fires were set in common areas in the three-storey elderly residential complex.
Firefighters were first alerted when sprinklers activated in the building shortly after 11pm (AEST) on Sunday.
Mr Woodward said firefighters may have been on the scene as some of the fires were lit.
"When they arrived they located one fire but then they discovered three other fires had been lit, so whether they were lit before we arrived or after we arrived is not quite clear," he told AAP.
Mr Woodward said the fires were small and were kept from spreading by the sprinkler system, but fire crews remained on the scene for four hours in case other fires broke out.
No one was hurt, Mr Woodward said.
Police are investigating.
