FIREFIGHTERS have been called in from across western Victoria to battle a supermarket blaze that caused more than $4 million damage.

Crews were deployed from brigades up to three hours away to fight the fire, which broke out at the IGA supermarket in Portland, in southwest Victoria, about 4.30am (AEST) today.

Country Fire Authority operations officer Gary Harker said it took firefighters more than two hours to control the fire, which gutted the front of the Percy Street supermarket.

He said 25 local firefighters managed to stop the fire from spreading before more firefighters from as far afield as Ballarat, Hamilton and Warrnambool arrived to help fight the blaze.

The damage bill was conservatively estimated at more than $4 million, with extensive stock losses expected.

Nearby properties were not affected.

Fire investigators will arrive at the scene this afternoon to examine the cause of the blaze.

Meanwhile, a post office and a butcher in the regional city of Bendigo were also destroyed in a separate blaze.

The fire started in Boydies Butchery, in Murphy St, Kennington, just after 7am (AEST) and spread to the adjoining post office, the CFA said.

A CFA spokesman said both properties were destroyed in the blaze.

The cause is being investigated.