More houses have been damaged by a massive bushfire burning out of control north of Melbourne.

The fire impacted houses in Wallan and Kilmore overnight and continues to run fast despite mild weather conditions, fire authorities say.

Emergency warnings remain in place for towns of Wallan, Darraweit Guim, Bylands, Kilmore and Kilmore East.

Victorian Fire Services Commissioner Craig Lapsley says more houses were badly damaged overnight.

“We have had fires run again in the northern parts of Melbourne, so at Wallan, which is an outer metropolitan area, houses were impacted,” he told the Nine Network.

“We believe up to five houses have been significantly damaged in that area.

The same fire had impacted houses further up at Kilmore, he said.

Mr Lapsley said the fire crisis will continue until Victoria gets significant rain.

“The fact that we are seeing these fires still run in conditions that aren’t extremely hot, not very strong winds and they’re running really hard, it tells you that the dry conditions remain and until we get rain in Victoria this won’t go away,” he said.

The state was in for a long fire season through to the end of February, he said.

So far 21 houses have been confirmed destroyed across the state and several hundred thousand hectares of land have been burnt.

Victorian Premier Denis Napthine said the Kilmore fire was 50km long and had broken out on the flanks to the east and west.

He said another eight to 10 homes may have been lost or affected.

“Fortunately, our highest priority has been protecting lives and at this stage there is no lives lost and no serious injury,” he told the Nine Network.

“So we certainly have learned the lesson from Black Saturday and we certainly have made significant improvements in our warning systems and in all our agencies working together to protect lives and property here in Victoria.”

Haze from the bushfires has reached central Melbourne.