Emergency Management Commissioner Andrew Crisp says it's possible the Strathallan fires had been lit by arsonists.

He said Victoria Police was investigating those five fires, which had forced six families to safely evacuate.

“Again we’re throwing significant resources onto that fire, and I know there’s strike teams coming from across the state to help out.”

He added that the next most significant fire was at Natte Yallock, north of Avoca.

It was started by a lightning strike and has caused “significant loss of pasture and crop” but has been reduced to a “watch and act”.