A week-long special hearing has started in the Warrnambool court with electricity giant Powercor attempting to get six charges thrown out that were laid after the St Patrick's Day bushfires in March 2018.

Powercor barrister Tim Margetts, QC, questioned the validity of the charges and applied on Monday for them to be struck out during the opening day of the case in Warrnambool Magistrates Court.

The charges related to two incidents, one involving clashing conductors at Terang that sparked what was known as the Terang/Cobden fire on St Patrick's Day, destroying more than 20 houses. The second related to a power pole that snapped on a property at The Sisters, sparking a fire known as the Garvoc blaze, which wiped out at least two houses, 4000 hectares and stock.

Victims have previously been awarded more than $22.5m in compensation.

In an outline of the case, Mr Margetts said there needed to be an understanding of the relationship between Powercor and regulator Energy Safe Victoria, which was prosecuting the current case.

He said there was an ongoing and continual flow of information between Powercor and the regulator ESV.

"We say in essence we lay all our cards on the table. ESV knows about what we are doing in relation to all our assets," he said.

Mr Margetts said that prior to the St Patrick's Day bushfires on March 17, 2018, ESV made no complaints about Powercor and no recommendations that Powercor do anything differently.

He said that situation had existed for "years and years and years"

The barrister said Powercor's inspection and maintenance regime was understood and assessed by ESV.

Mr Margetts said what Powercor wanted to know now was - what does ESV say that the company should have done that it was not doing?

"ESV knew and approved of what we were doing," he said.

Mr Margetts said ESV knew how Powercor managed its network and the company would allege that complying with the inspection scheme was a defence to the current charges.

He said that Powercor annually submitted a bushfire mitigation scheme. ESV looked at that maintenance plan, made an assessment and in fact audited the bushfire mitigation plans, which included inspection of poles and pole tops.

He said if there was something Powercor should have been doing then that should have come out in the ESV audit reports.

He said this week's special hearing would focus on bushfire mitigation plans for the years 2017 and 2018 - immediately prior to the St Patrick's Day fires and immediately after the blazes.

"If there was going to be a criticism of the inspection regime one would expect to find it there (in those audits)," Mr Margetts said.

"They basically work together to prevent bushfires. Criticism by ESV is welcome. The last event Powercor wants is bushfires.

"We say documentation exchanged between them (ESV and Powercor) is critical to assess the validity of these charges."

Mr Margetts said Powercor had more than 560,000 poles and 67,000 kilometres of wires and an inspection plan was put in place which ESV had approved and accepted.

He said Powercor undertook an enormous task.

"What measures does ESV say we should have been undertaking, that we don't, to ensure there's not a breach of our duty," he said.

The barrister said the relationship between ESV and Powercor involved a flow of information, which was very different to how many other authorities operated, such as WorkSafe.

Powercor's network covers more than half of Victoria, much in high risk bushfire areas.

Powercor inherited the electricity network after the State Electricity Commission was privatised in 1994.

Earlier: Electricity giant Powercor is today appearing in a special hearing in Warrnambool court 40 months after fires started at Terang and The Sisters on St Patrick's Day 2018.

Powercor is facing six charges relating to two incidents:

The charges laid are for breaches of the Electricity Safety Act general duties under Section 98.

They relate to Powercor's failure to operate and maintain its network to minimise as far as practicable:

Powercor faces two counts of each charge, one for each fire.

The maximum penalty for each offence is $250,000 - so if Powercor was found guilty, the maximum possible fine would be $1.5 million.

The charges have been filed at the Warrnambool Magistrates Court with the five-day hearing starting on Monday.

Former Energy Safe Victoria director Paul Fearon previously said this was the first case of its type against an electricity distributor.

"For that reason it is a very important test case," he said.

"It will be a point for what conduct is necessary to meet the standard and general duty, which is minimising the risks as far as practicable.

"If anything it demonstrates that we are prepared to take action and we have the capability to do it," he said.

The announcement of charges comes after a Supreme Court class action involving Terang/Cobden bushfire victims was previously held in the Warrnambool court complex.

Four main St Patrick's Day fires swept through Victoria's south-west on March 17, 2018 - at Gazette, Camperdown/Gnotuk, Terang/Cobden and The Sisters/Garvoc.