SYDNEY (AFP) - Survivors of a devastating 2009 bushfire in Australia won a nearly A$500 million (S$582.5 million) payout on Tuesday in the biggest class action settlement in the nation's history.

The Kilmore East blaze was the largest of the "Black Saturday" February 2009 wildfires in southern Victoria state that left 173 dead and razed more than 2,000 homes, the nation's worst natural disaster of modern times.

More than 10,000 people joined the action against SP AusNet over the Kilmore inferno, which killed 119 people and caused an estimated A$1 billion in damage. SP AusNet is 31.1 per cent owned by Singapore Power.

Lead plaintiff Carol Matthews, whose son Sam burned to death, claimed the power company's faulty equipment ignited the blaze, with lawyers saying the resulting fire, which razed 125,000 hectares, was "entirely preventable".

SP AusNet said in a statement that the settlement was reached without admission of liability by the company or any other party.

The group also sued Utility Services Corporation Limited, which was contracted by SP AusNet to maintain the line, and the Department of Sustainability and Environment for allegedly failing to reduce fuel loads.

"The conductor which broke and which initiated the fire was damaged by lightning, compromising its fail-safety design in a manner which was undetectable at that time," SP AusNet said.

"This point was accepted by experts called by all parties who provided evidence in relation to the conductor break.

"It is a tragedy that the conductor eventually failed on one of the worst days imaginable," it added.

Maurice Blackburn lawyers said the payout was more than double the previous highest Australian class action settlement of A$200 million.