A former volunteer firefighter who started a blaze that killed 10 people and destroyed more than 150 homes on the day of Australia's "Black Saturday" bushfires was Friday jailed for at least 14 years.

The Victorian Supreme Court last month found 42-year-old Brendan James Sokaluk guilty of arson causing death over the fire he caused at Churchill in February 2009.

Sokaluk started a blaze on "Black Saturday", the day on which a series of simultaneous bushfires raged in extremely high, dry and windy conditions across Victoria state and left 173 people dead in the nation's worst natural disaster.

Justice Paul Coghlan sentenced Sokaluk to 17 years and nine months in jail with a non-parole period of 14 years, saying he had taken into account his mild intellectual disability and autism spectrum disorder.

In sentencing, Coghlan said he was satisfied that Sokaluk lit two fires on the afternoon of February 7, 2009 which rapidly spread and eventually developed into an out-of-control firestorm which destroyed more than 150 homes.

"I am also satisfied that you did not intend to kill anyone," he said.

Coghlan said the fire was a serious one, fanned by gusts of up to 65 kilometres an hour (40 mph), which had "truly catastrophic consequences" after a sudden wind change in the early evening.

The court heard that Sokaluk set the fires on a day in which the temperature in the area hit 46.3 degrees Celsius (114 Fahrenheit).

Coghlan said no sentence he could impose would provide compensation for the loss to the victims' families but noted it "does bring to an end one part of the process".

Rhonda Jacobs, who lost three family members in the Churchill blaze, welcomed the sentence.

"Justice has been done and we're grateful, even though were leaving behind much-loved family," she told reporters.

"We now have a grandson without a father, mother or brother."

Sokaluk, who admitted starting the fire but told police he had dropped cigarette ash out of his window and it had been an accident, was a Country Fire Authority volunteer in 1987 and 1988.