Sydney restaurant Porteno damaged in fire

Twenty staff were forced to flee a popular Surry Hills restaurant after a fire broke out on Friday afternoon.

Fire and Rescue was called to Porteno on Cleveland Street about 5pm on Friday, January 9, as thick smoke billowed from the building.

Police said between 15 and 20 staff were inside the building when the blaze started, but all escaped uninjured.

The fire has been deemed as not suspicious. It is not known what caused the fire.

The blaze sparked traffic chaos in the busy inner-city suburb, shutting down Cleveland Street until 7.30pm in both directions between Elizabeth and Crown street.

The fire had been extinguished by 6pm. Firefighters remained on the scene for several hours extinguishing hot spots.

Duty Commander for City of Sydney Kernin Lambert said when firefighters arrived on the scene they thought they were going to lose the building.

"The roof was well on fire and there were a lot of flames," Lambert said. "21 people, all staff, self evacuated when they noticed the fire. It took an hour to put out the fire and there were 50 firefighters here.

"The fire was in the kitchen and we believe it had something to do with the kitchen exhaust.

"It's going to be out of service for a long time. About 80 per cent of the restaurant we managed to save.

"The owners are in shock and have now had a look inside the building."

The co-owners of the restaurant were unwilling to speak about what may have started the fire, or how long they may remain closed.

They told Fairfax Media they were at another event at the time the fire broke out, and rushed to Surry Hills to find staff and residents looking on as smoke poured out of the roof.

They said they were not allowed to go inside the restaurant even after the fire had been extinguished. One manager was heard telling staff not to come into work tomorrow.

Andrew Barrett, who lives across the road from Porteno, said they were not sure what caused the fire.

"There was a lot of smoke. There was a [firefighter] up the top trying to help," he said.

"We were like 'what the hell is going on'.

"We heard the sirens from down the street, cars were still driving past when it was on fire."

With Nick Ralston