Good Samaritans 'prevented' hatchet killing, jury told

A jury in an attempted murder trial has been told "good citizens of Brisbane" were the reason why a man's alleged hatchet murder plot was foiled.

Cameron Turgay Bardak faced trial in the Brisbane Supreme Court on Monday after pleading not guilty to attempting to murder his ex-girlfriend with a hatchet and by strangulation on July 1, 2020 in a CBD multi-storey car park.

Bardak, then aged 29, had pleaded guilty as an alternate charge to causing grievous bodily harm to the woman, then aged 27, whose hand and finger were struck by the hatchet, had a clump of hair pulled out and throat injured during the attack.

Crown prosecutor Chris Cook did not accept that plea, telling the jury Bardak had formed the idea about the victim that "if I can't have her, nobody will".

The jury was shown iPhone footage of Bardak on top of the victim with his hands around her throat while multiple people tried to separate them.

"He planned to kill his recently ex-girlfriend as she left work that day via the car park at 280 Adelaide Street. He had been there before. He knew how to get in and out of there," Mr Cook said in his opening statement.

"Mr Bardak is a powerful man...(the victim) was slightly built at 167cm and 55kg."

Mr Cook said the relationship had broken down after heated arguments over money, Bardak's desire to get married and his inability to control his anger.

The jury was shown CCTV footage of Bardak buying a large crowbar and a smaller hatchet at a Mount Gravatt Bunnings store about 90 minutes before the assault.

Mr Cook told the jury they might decide Bardak allegedly yelling at the victim that he wanted to kill her and later telling police he wanted to kill himself showed plans for "some kind of cowardly murder-suicide attempt".

"Perhaps the only reason he was unsuccessful was the good citizens of Brisbane: strangers who came to help (the victim). A couple of good Samaritans who could hear her cries for help," Mr Cook said.

Bardak's barrister Matthew Hynes told the jury in his opening statement the "real issue" in the trial was to establish his client's intent at the moment he attacked.

"The prosecution must prove beyond reasonable doubt that the intention behind each of the blows and acts was to kill. Nothing short of that will do," Mr Hynes said.

He told the jury they could use their common sense and life experience.

"Mr Bardak could have no future if (the victim) was dead; no chance of a relationship, no chance of marriage," Mr Hynes said.

"He's not here to defend his acts. He hurt people and he accepts that...let's see what the evidence tells you about intent."

Bardak also pleaded guilty to unlawfully wounding one of the people who came to aid the victim, but that charge was not taken to trial.