David Honey shared the video on social media this week, describing 2021 as "the most violent year in WA's history".

The video includes TV news reports of violent incidents including a group of teenagers being bashed while celebrating Australia Day at City Beach.

But it also includes footage of a shopping centre brawl that took place in the Queensland city of Toowoomba last year.

Other footage used in the video dates back as far as October 2017.

The video notes that a record high of 53,370 violent crimes were committed in WA last year. WA Police statistics indicate more than half related to family violence offences.

"Last year was the worst in WA's history for violent crime. WA Labor is #WeakOnCrime!" Dr Honey wrote.

He said he was unaware of the gaffe after being asked by reporters on Tuesday about the video.

"It makes no difference to the point we're making and that is, violent crime in Western Australia is out of control under this Labor government," Dr Honey said.

Police Minister Paul Papalia seized upon the Liberal leader's error.

"It demonstrates just how poor the level of research is and the standards to which the Liberal Party have dropped in Western Australia," he said.

"It's a very sad situation."

Dr Honey posted the video days after two young women were bashed in a carpark in the trouble-plagued entertainment precinct of Northbridge.

Two men have been charged in relation to the attack.

Mr Papalia described the incident as "shocking" but said police had responded swiftly.

"An alert was raised by police in the Perth camera room and within 33 seconds, those individuals were under arrest," he said.

"I think that's an incredible response by the West Australian police force and confirms that whatever concerns anyone may have about activities in Northbridge, lack of policing response shouldn't be one of them."

Dr Honey was elected unopposed to lead the Liberals last year after they were reduced to just two lower house MPs in a disastrous state election performance.

His party entered into an informal alliance with the Nationals, whose leader Mia Davies became the state opposition leader.

Dr Honey was last week forced to apologise in parliament after he claimed Health Minister Amber-Jade Sanderson "worries more about fashion than she does about doing her job".

Ms Sanderson rejected the apology, describing the comment as sexist and misogynistic.

Australian Associated Press