Firefighters are monitoring a number of Carlton businesses closely, after a suspicious blaze ripped through the buildings leaving a $2 million damage bill.
The fire started just before 1am on Monday in a two-storey building under renovation on Lygon Street, with reports of witnesses hearing explosions as the inferno took hold of a reception centre next door.
A wall collapsed into a laneway, while a Japanese restaurant and reception centre were decimated by the blaze, which firefighters brought under control after just over an hour.
Fifteen people were evacuated as a precaution and up at a Travelodge Motel until it was safe to return.
The street is closed southbound down to Grattan Street and Grattan Street is closed heading east as police investigate the cause and MFB crews work to ensure the blaze is fully extinguished.