Graphic video footage of a Perth man being tasered after a random breath test has damaged public confidence in the Western Australian police force, its head of professional standards has conceded.

But WA Assistant Police Commissioner Nick Anticich will not accept the finding of the Corruption and Crime Commission (CCC) that a WA Police officer tasered the man for "no good reason" after a routine breath test in Fremantle last year.

While he said the CCC report released on Wednesday was "damning" and the footage looked "terrible", Mr Anticich said he did not understand how an internal WA Police investigation and the CCC could have come to such different conclusions on the incident.

"How is it that we say the actions of the officer in this instance were justified, yet the Commissioner's come back with a finding of serious misconduct?" he told ABC Radio.

"We need to understand why and what were the facts on which they based that position of serious misconduct."

Justified or unjust?

The video — which begins just before the tasering and captures many events afterwards — was filmed by one of two passengers in the vehicle driven by the taser victim, who was given an assumed name of "Bill Holt."

The trio were heading out to dinner when Mr Holt was breath tested.

He recorded a blood-alcohol level of zero but police officers issued his car with a defect notice, prompting some backchat from the men, one of whom was alleged to have said: "You are jealous of my car, you are too poor to afford this car".

The CCC disputes the officer's use of the taser was justified. ( ABC News )

The situation quickly escalated and ended with Mr Holt being tasered, arrested and held in custody at Fremantle police station.

The tasering police officer, identified only as Senior Constable Keenan, was stood aside from public duties after the report was released and while WA Police's internal affairs department reviews the incident and how it was investigated.

The key point of difference between WA Police and the CCC is whether the officer was justified in using a taser.

In particular, it centres on two allegations by police which are disputed by the CCC:

Mr Holt assaulted Senior Constable Keenan by grabbing his hand as he went to take keys out of the ignition

Mr Holt assaulted Senior Constable Keenan by grabbing his hand as he went to take keys out of the ignition Senior Constable Keenan was standing in front of the car and was under threat of being run over because the car's engine was still running

Police deny taser problem

The video showed an officer using her hat to block her face from being filmed. ( Supplied: CCC )

Under WA Police policy, tasers may only be used to prevent injuries and never to enforce compliance.

But the CCC was highly critical of the various police investigations into the incident, saying they were used to identify ways of making Senior Constable Keenan's use of a taser lawful and justified.

For example, the report said police reviews had incorrectly concluded that video evidence showed Mr Holt assaulted Senior Constable Keenan by grabbing his hand.

"The statement of investigators of reliance on the incident video to establish that Mr Holt did grab hold of S/C Keenan's hand and wrist is troubling," the report said.

"The incident video did not capture this occurring."

The report also found the car's engine was not running when Mr Holt was tasered.

His vehicle was heard in the video to make a chiming sound — a sign that the car engine had been turned off — before the taser was deployed.

Mr Anticich denied that WA Police had a problem with tasers, saying he was "almost certain" it was an isolated incident and complaints against police use of tasers were rare.

"I think you could count them on one hand and that extends over a period of 10 or more years," Mr Anticich said.

Some of WA's high-profile tasering cases

The Walker family

Mr Walker was pepper sprayed and tasered outside a CBD bar in January 2010.

In January 2010, Ken and Raelene Walker, their son Ryan and his friend Luke Hazell became involved in an argument with police outside Tiger Lil's bar in Perth CBD.

Ryan was pepper-sprayed and tasered, and his mother's ankle was broken.

Ryan was accused of punching a police office and his parents were charged with obstructing police.

But the charges were dismissed after it was proved that CCTV footage did not demonstrate an assault by Ryan.

The incident led to an apology by former WA Premier Colin Barnett.

Catherine Atoms & Robert Cunningham

Catherine Atoms and Robert Cunningham stopped to help to pull four men out of a flower bed after a night out in Fremantle in November 2008 but the situation quickly escalated after police became involved.

The couple was accused of disorderly conduct, resisting arrest and assault - allegations which were discounted by different courts - and were handcuffed, tasered and arrested.

Awarding the couple more than $1.1 million in damages in 2016, District Court judge Felicity Davis found the officers fabricated evidence, abused their powers and falsely imprisoned, assaulted and tasered the couple.

Catherine Atoms and Robert Cunningham received more than $1 million in damages for false imprisonment and assault. ( ABC News: Manny Tesconi )

Current and previous parliamentary inspectors of the CCC have criticised the "demonstrably flawed" internal police investigation into the incident.

This review was conducted by staff who worked at the same police station as the officers, cleared them of misconduct and failed to interview the officer who tasered the couple.

Kevin Spratt

Disturbing footage taken inside the Perth Watch House in September 2008 showed Kevin Spratt screaming in agony as he was tasered 14 times after refusing to go to a cell to be strip searched.

But the vision was not released until late 2010 by the CCC, which took over the investigation of the incident around this time.

CCTV footage shows Kevin Spratt being tasered 13 times in the East Perth watch house.

The CCC was critical of the police internal investigation and made misconduct findings against two officers in its April 2012 report but deemed seven deployments of the taser as appropriate.

The police officers - Aaron Strahan and Troy Tomlin - were later found guilty by a Perth magistrate of three charges of assault related to the tasering.

An internal police investigation resulted in the men being disciplined and fined, and former WA Police Commissioner Karl O'Callaghan sent a letter of apology to Mr Spratt.

But the CCC was later criticised by a parliamentary committee for not investigating the incident earlier.