Cameron Ashcroft, 23, and Todd Elphick, 26, have pleaded not guilty to a charge of conspiracy to intentionally inflict grievous bodily harm.

Kai Yuen, 28, confessed to gunning down his former long-time friend Brendan Scott Welsh, 28, near the Hughes shops in May 2010.

Ashcroft and Elphick are accused of agreeing to help shoot Mr Welsh in the foot.

Yuen had been involved in a feud with Mr Welsh sparked by a dispute over a car weeks earlier.

The dispute continued with a number of tit-for-tat incidents, including threats and property damage, and escalated after the window of Yuen's work van was smashed.

Yuen collected a shotgun from his rented Gowrie home and was driven by Elphick around the city for more than three hours in an attempt to find Mr Welsh.

Yuen recruited Ashcroft to lure Mr Welsh to Hughes under the pretense of buying drugs.

Two rounds were fired into the car, with one blast fatally hitting Mr Welsh in the chest.

In his opening submissions on Monday, prosecutor Shane Drumgold told jurors the plan to “blow [Mr Welsh's] foot off” had been mentioned at an April meeting between Yuen and the accused men.

He said the pair knew what was going to happen at the confrontation between Yuen and Mr Welsh.

Elphick's defence barrister, John Purnell, SC, admitted his client was no angel but said he had not agreed to a plan to shoot Welsh.

Mr Purnell told jurors Yuen had acted “like a total idiot by himself” by taking a loaded gun to the confrontation and shooting Mr Welsh.

The lawyer said that Elphick had merely been told where to drive and when.

Ashcroft's lawyer, John Harris, SC, said his client was a drug addict and unwitting participant in the incident.

The trial before Justice Hilary Penfold continues on Tuesday.