It will also consider practices of officers working solo on some patrols, the Victorian Coroners Court has been told.

The inquest comes 4 years after Knox-based regional traffic tasking unit's Senior Constable Tony Clarke, 37, was murdered by a motorist he had pulled over for the second time in one shift, on Warburton Highway at Launching Place.

The motorist, Croydon's 27-year-old Mark Bailey - who the inquest heard blew .107 when pulled over for the second time about 1.20am on April 24, 2005 - then drove Senior Constable Clarke's unmarked police car to Mt Evelyn where he used the gun to take his own life.

Steven Milesi, counsel assisting coroner Kim Parkinson, said Senior Constable Clarke, who was working solo as part of a traffic operation targeting drink-drivers in Yarra Ranges, had issued Bailey with a speeding fine earlier in the evening, about 10.34pm, as he travelled between two parties. At that time, a breath test revealed no presence of alcohol.

He said that when Senior Constable Clarke pulled Bailey over a second time, about three hours later, witnesses saw what appeared to be a struggle between two men.

Robert Taylor, counsel for Senior Constable Clarke's widow, Tina Hogarth-Clarke and the Police Association, argued in his opening statement that there would have been no reason for Senior Constable Clarke to draw his weapon under the circumstances.

He said Bailey must have grabbed the weapon from the policeman's holster.

Mr Taylor said that for two years, high-ranking officers "knew the holsters were deficient and knew it was an issue that could prove fatal", adding it could prove "not only negligence but perhaps gross negligence".

On the issue of solo patrols, he said it was "almost unarguable that had he been working with a colleague his death would not have occurred".

But counsel for Victoria Police, Gerard Maguire, said the evidence was "intangible at best" and there were several scenarios that could have resulted in Bailey coming into possession of the gun.

He argued that Victoria Police had acted appropriately and in the best interests of its members and had provided training to prevent "the person seeking access to the weapon from getting to it".

Following the opening addresses, lawyers and coroner Parkinson visited the Wesburn Hotel, where Bailey had been drinking before the incident, and the scene of the shooting and the scene of the suicide.

The inquest continues.