Two persistent fires that had destroyed homes and killed animals in the state's north east were brought under control on Thursday evening. It was the first time Victoria had been without a fire threat in days.

The 5740 hectare Lake Rowan fire, north of Wangaratta, was declared contained after 10pm, with crews halting its spread with containment lines.

Fire conditions also abated at the Creightons Creek fire, near Euroa, which destroyed three homes earlier this week after it was sparked by a dry lightening strike on Tuesday.

Although crews still patrolled the fire ground, residents were being let back into areas that had been affected by the blaze.

In the meantime authorities were investigating the cause of a blaze in the Heathcote wine region which had residents alarmed on Thursday when it threatened Mia Mia, Meadow Valley and Glenhope.

Norbert Baumgartner, owner of the Mia Valley Winery and a CFA volunteer, said he believed the fire was a flare-up of another started by a slasher Wednesday night.

"I noticed a plume of smoke while I was working in the vineyard ... We all knew this was going to be a very bad season, but it started early," he said. "Everything's bone dry, we've had no rain for months."

Just 280 hectares were burnt before the blaze was brought under control, with authorities throwing significant resources into the battle. More than 300 people and 120 vehicles were deployed in the fire fight.

By mid-afternoon the blaze had been contained.

This week lightning has sparked more than 350 fires around the state.

On Thursday evening the CFA was keeping a close eye on a forecast cool change. A state control centre spokeswoman said the change could bring blessings in the form of cooler temperatures and some rain, but possibly also some challenges: lightning and 40 km/h winds.

As of 11pm Thursday there were no fire threats to communities, but the CFA were still urging the public to stay informed and monitor conditions.