A report into the police handling of former treasurer Troy Buswell's series of crashes in his ministerial car has found "systemic failure at a number of levels".

A Labor-dominated parliamentary committee found there was "an inadequate police response" into the Liberal MP's actions in the early hours of 23 February, when he crashed into several cars in Subiaco on his way home from a wedding.

The Member for Vasse was fined and disqualified from driving for a year after pleading guilty to offences related to the incident.

The Community, Development and Justice Standing Committee report found the incident had the potential to compromise the public message that alcohol and driving do not mix.

Committee chair, Labor MP Margaret Quirk, told Parliament that police let the investigation "lapse", with the media ultimately forced to "join the dots".

"The media attention that this incident has received has also drawn attention to the limited nature of the police response and raises questions about the value of campaigning on drink-driving if enforcement is so publicly mediocre," she said.

The committee's report said the prosecution's advice from State Solicitor's Office was "conservative" and based on raft of assumptions.

It said "with different assumptions, the advice could have been to pursue a driving under the influence charge".

The report also stated that the police investigation "was conducted under the erroneous assumption that no charges could be laid, in the absence of a breathalyser reading".

Liberal committee members Ian Britza and Chris Hatton have submitted minority reports disagreeing with the committee's findings.

Mr Hatton has told Parliament "significant omissions, broad assumptions and incorrect conclusions" were contained in the review, which he said was compromised by partiality and bias.

"While I strongly acknowledge, along with the committee that drink driving is serious and should result in a drink driving charge and conviction, the evidence surrounding this incident could not be supportive of that charge or conviction," he said.

Police boss says he won't 'wipe noses' of MPs

Police Commissioner Karl O'Callaghan has defended the investigation and said the committee's report was at odds with previous reports into the incident.

"Well, it's very interesting because there are two minority reports also that disagree with those findings, so the minority reports actually talk about incorrect assumptions and admissions, so you have a parliamentary committee that can't even make up its own mind about what the outcome should be," he said.

Mr O'Callaghan rejected claims his officers failed to properly investigate the crash, saying the full extent of the damage was not revealed until two weeks later.

He said it would have been helpful if police were aware that the home they traced the car to in Subiaco was owned by Mr Buswell.

"But it does require members of Parliament to advise the WA Police Dignitary Protection Unit where they live," he said.

"Now one of the things this says is that I should run around chasing up members of Parliament.

"My view is that's an extremely arrogant approach. They are responsible for giving me their details.

"I am not going to chase them around and wipe their noses for them."

During committee hearings Mr O'Callaghan was questioned over why police failed to follow up any potential drink-driving charge against Mr Buswell, despite the fact the job was listed under job code 317, the code for driving under the influence.

The committee was told police responded to a call about the events within 10 minutes, and Mr O'Callaghan said he was not sure the response "could have been any better".

MPs were told police officers spent nine minutes at Mr Buswell's house, and while they could see minor damage to the fence they had no legal right to enter property.

Barnett disputes bottle dumping claims

Premier Colin Barnett has disputed claims Mr Buswell was spotted dumping bottles on government premises around the time of the car crashes.

The committee's report includes evidence a security guard spotted Mr Buswell emptying bottles into a bin in the basement of a government building around the time of the incident, but was never interviewed.

The Opposition seized on the findings, demanding another inquiry.

But the Mr Barnett told Parliament that Mr Buswell didn't appear on CCTV footage taken from the building in the hours leading up to the incident.

"Mr Speaker, the leader of the Opposition has been in the gutter right through this issue," he said in Parliament.

"And Mr Speaker, at no stage have I excused or condoned the actions of the Member for Vasse, Mr Speaker.

"But the leader of the Opposition has perpetuated this myth of a cover-up."

Opposition Leader Mark McGowan said Mr Barnett needed to explain other details in the report, including why police had Mr Buswell's fingerprints on file.

"It's like pulling teeth trying to get to the bottom of these events, and Mr Barnett as Premier needs to provide a full explanation of what has gone on," he said.

"He needs to call Mr Buswell in and demand an explanation."

Insurer seeks advice on whether Buswell to pay for damages

Meanwhile the WA Government's insurer is seeking legal advice about whether it can ask Mr Buswell to pay for damage to his ministerial car.

It was revealed in State Parliament on Wednesday that it cost almost $15,000 to fix the vehicle.

Mr Barnett said it was an issue for the two parties involved, but he understood the public expected Mr Buswell to cover the repair costs.

Mr McGowan said the Premier had refused to hold Mr Buswell to account.

"We know what happened. Mr Buswell is not charged with drink-driving, despite the fact he should have been," he said.

"The Government is picking up the tab for Mr Buswell's... careless driving and that is unacceptable."

Buswell suffered breakdown

Mr Buswell suffered a breakdown after the incident, took leave from Parliament and relinquished his Treasury and Transport portfolios.

In April he pleaded guilty to 11 traffic charges related to the incident.

He was fined more than $3,000 and banned from driving for 12 months.

He later revealed he suffered from bipolar disorder and depression, and apologised for his behaviour.