Emergency crews were called to the scene on Nelson Street, Sebastopol about 11.30pm, finding the rear of the house fully engulfed.

Five vehicles from Sebastopol, Lucas, and Ballarat Central attended, taking about half an hour to fully extinguish the blaze.

No one was injured.

The house suffered extensive damage, according to firefighter Peter Egan.

"Nobody home at the time, which was fortunate, particularly at that time of night," he said.

"Our crews worked hard to contain the fire, and support the family who were the residents."

While there is no word yet on the cause, investigators were on the scene Sunday morning to find out more.

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