Stephen Tahaney, who admits pulling the trigger and shooting Mr Morgan in the head, asked him where he wanted to meet up.

Those aren't the actions of people who are planning on killing someone, defence lawyers have told a Victorian Supreme Court trial.

The two men along with Jack Harvey are accused of being part of an agreement to harm Mr Morgan in Point Cook in Victoria in 2019, knowing he'd probably be killed.

Tahaney says he pulled the trigger in self-defence during a dispute with Mr Morgan, who had been asked for help by his longtime friend Daniel Saddik whose business dealings with Tahaney and Dixon's brother had soured.

CCTV footage shows the three Irish nationals arriving in a suburban Point Cook street where they're approached by Mr Morgan.

After a report of fighting, a witness saw one of the men go back to the car, point a gun out the window and fire a single shot, which struck Mr Morgan in the head.

Tahaney's barrister Julie Condon QC said Mr Morgan brought the gun, not her client.

"In 1995 he resorted to his police issue revolver to execute his brother-in-law and that's what he intended to do in 2019 - resort to firearms," she said.

Mr Morgan was acquitted of murdering his brother-in-law in Sydney in 1995 after shooting him six times in the head over allegations the man had sexually abused children.

Ms Condon said Tahaney ended up in a situation where he had to pull the trigger of Mr Morgan's own gun, and that he did it in self-defence.

She also disputed there was any agreement to go there to kill or harm Mr Morgan that night.

Text messages to Mr Morgan show they were asking where he wanted to meet, she said.

"You don't say to a person you're intending to kill 'where do you want to meet', you say 'meet me here' because you're calling the shots," she said.

Tahaney and Harvey were wearing light coloured clothing while Dixon was wearing a hi-vis shirt with the logo for his company Oz Property Maintenance.

"Is that the sort of clothing you'd wear when you're going around to kill someone? That doesn't sound right to me," she told the jury.

Dixon's barrister Geoffrey Steward said it was Mr Morgan and not the accused men who had been making death threats.

"You and your brother are about to pay the ultimate price," he said Mr Morgan wrote to Dixon, referring to them as "dead men walking".

Dixon replied: "Your texting shows just how much of a clown you are".

The trial is continuing.

Australian Associated Press