A FIRE has half destroyed a Portland supermarket causing about $4 million damage.
Portland fire brigade officer-in-charge Gary Harker said police officers saw smoke coming from the Percy Street IGA supermarket and raised the alert at 4.38am this morning.
He said thermal imaging cameras were used to track and then fight the fire which was contained by 7am.
Mr Harker said about 50 per cent of the supermarket had been destroyed.
He said the fire is believed to have started in the front section of the supermarket, before entering the roof space and spreading throughout the building.
"It's a major structure and half the building has been damaged," he said.
"It was a heavy fire when we arrived and locked up. We vented the building and used thermal imaging cameras to locate the fire."
Mr Harker said about 70 fire fighters had battled the blaze with men called in from as far away as Ballarat and Geelong.
"The fire is contained and we're continuing blacking out and mopping up works. The investigation into the cause of the fire will take place this afternoon, but half the building has been gutted," he said.
Police blocked off roads and cranes were used to gain access to the roof.