The Victorian Supreme Court has been told electricity distributor SP AusNet should have known a faulty powerline could cause a bushfire that killed 119 people on Black Saturday in 2009.
In the biggest civil case in Victorian history, 10,000 plaintiffs allege negligence on the part of SP AusNet and Utility Services Corporation that led to the Kilmore East Kinglake bushfire.
The blaze razed 125,000 hectares and destroyed more than 1,000 homes.
In his opening address, counsel for the plaintiffs Robert Ritcher QC told the court the cause of the fire was not in dispute.
He said the defendants were aware that older and faulty electricity infrastructure could cause a devastating bushfire in extreme weather conditions but failed to take steps to make it safe.
He said SP AusNet was aware of previous lightning strikes that had damaged the powerlines.
Ahead of the hearing lawyer Andrew Watson said SP AusNet failed to properly maintain its infrastructure.
"They had in effect a policy that they describe themselves as 'run to failure', and what happened on Black Saturday is that that policy came to its logical fruition," he said.
"The line failed and caused the fire which caused the deaths of 119 people."
The Department of Sustainability and Environment, the Country Fire Authority and the State of Victoria are also being sued.