Powercor was charged with six offences after Energy Safe Victoria (ESV) investigations found fires at Terang and Garvoc were caused by failing infrastructure.

But on Monday, all but one charge was withdrawn, including all those relating to a collapsed, rotted power pole that started the Garvoc blaze in March 2018.

The energy giant pleaded guilty to the remaining charge of failing to minimise the risk of bushfire after clashing conductors caused a fire at Terang's High Street.

ESV issued a media release on Tuesday confirming they'd withdrawn the bulk of the charges against Powercor but did not provide an explanation.

Member for Polwarth Richard Riordan this week in parliament demanded answers from ESV and the Minister for Energy, Environment and Climate Change Lily D'Ambrosio.

He said the community had waited three years for resolution on what "was a terrible event for that community".

"ESV's media release in October 2019 said they made the decision to lay charges to head a long and complex investigation and to demonstrate they were prepared to hold businesses account, and now after three years, they're simply just walking away," Mr Riordan told The Standard.

"No one is being held responsible. Minister D'Ambrosio and ESV chairman Marnie Williams need to come to the south-west and explain.

"There were tens and tens of millions of dollars of damage and lives are still in ruin in those communities. They're devastated."

Mr Riordan said startling data released by ESV in the year after the fires showed existing power poles were well past their use-by-dates, leaving communities fearing for their future.

"There are some 800,000 wooden power poles, of which ESV's own documentation says 50 per cent are past their use-by-date," he said.

"The report is from 2019 so that figure will move to 70 per cent of poles within the next five or six years. They're ticking time bombs."

Mr Riordan said there was no evidence of the power poles being replaced quickly enough.

"People's lives are at risk and quite frankly there is little that people in our communities can have confidence in," he said.

"There are systemic underlying problems that may even have corporate negligence elements to it."

The Standard asked Minister for Energy, Environment and Climate Change Lily D'Ambrosio if she planned to visit the south-west to answer community questions following this week's court proceedings but she did not respond to the question.

She said she "welcomed Powercor's guilty plea and acceptance of failures that caused the Terang fire and I support ESV holding electricity companies to account when their performance falls below acceptable safety standards".

"I also welcome the new requirements on Powercor to significantly improve its pole inspection and maintenance regime since the fires," she said.

"We are building a stronger and fit-for-purpose energy safety regulator to keep Victorians safe and hold those who do the wrong thing to account."

Powercor will appear in court again on December 13 for a plea hearing.

The charge of failing to minimise the risk of bushfire carries a maximum penalty of $237,855.

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