But defence lawyers told a jury on Thursday the two men denied the allegations. One barrister said that the alleged victim had given multiple versions of what happened, and suggested the police officer who later complained held a grudge against one of the accused.

The ACT Supreme Court heard that Wade Joseph Howell, 36, was visiting from Melbourne for a training course. He was out drinking when early in the morning on April 2, 2016, he ended up at Civic nightspot Mooseheads. The alleged victim and his girlfriend were also at the club.

In her opening address, prosecutor Kylie Weston-Scheuber told the jury that the woman left the club and was followed shortly afterwards by Mr Howell, before they both sat down on a park bench.

It’s alleged the woman’s boyfriend came running towards them, and Mr Howell stood up and pushed him away. It’s alleged Mr Howell proceeded to beat the man, fracturing his cheek bone and giving him a bloody nose.

It's further alleged Mr Howell continued to beat and choke the man when he had fallen to the ground. The alleged victim told the court Mr Howell said: "I'm a police officer I will kill you."

"I said, 'Man I can't breathe please let me go'," the alleged victim recounted, and told the court his mouth had been "full of blood".

Feeling ill during the alleged fight the woman returned to the Medina Apartments where they were staying in Canberra, the trial heard.

On the Crown case, the two men got up. Mr Howell said they needed to talk to the woman, and they walked together to the Medina Apartments.

Dr Weston-Scheuber said Mr Howell said he had “f--ked up” and expressed concern about his career.

Once at the apartments, Mr Howell spoke to the girlfriend about domestic violence and then called police, saying he was with a woman who wanted to leave an abusive relationship, the trial heard.

Andrew Charles Smith, 46, was the acting sergeant with ACT Policing who arrived on the scene.

Prosecutors say Mr Howell and Mr Smith knew each other from when both were with the Australian Federal Police in Canberra. Mr Smith spoke to Mr Howell, and then to the girlfriend, before directing two other officers to arrest the alleged victim.

Mr Smith, of Forde, described Mr Howell’s actions as a “clear case of self-defence” and later asked to be assigned as the officer on the case.

Dr Weston-Scheuber said nowhere did Mr Smith refer to the alleged victim's injuries, and neither did he talk to the alleged victim for his version of events.

She said the officers had diverted, or in the case of Mr Howell, attempted to divert, police away from what had happened.

One of the constables at the scene was unhappy with what he had witnessed and filed a complaint, which eventually led to the criminal charges against the two officers, the trial heard.

Mr Howell is charged with recklessly inflicting grievous bodily harm, unlawfully choke and attempting to pervert the course of justice.

Mr Smith is charged with intentionally perverting the course of justice, and two alternative charges of urging unlawful confinement.

They have pleaded not guilty to all charges.

Barrister James Sabharwal, who acts for Mr Howell, said Mr Howell would tell the jury he saw an agitated man run towards him with his hands raised.

Mr Howell says he pushed the man away, but denied he had beaten the alleged victim, only punching him once on the body in self-defence, Mr Sabharwal said.

Mr Smith’s barrister Steven Whybrow said the charges stemmed from a constable on the scene taking a certain view “that Mr Smith was doing something untoward.” He suggested the constable had a "chip on his shoulder" about Mr Smith being appointed acting sergeant in the team.

He said police had the power to arrest people for intoxication, and that is what he'd done, “doing his job is, what I’ll be ultimately submitting to you.”

He asked the jury to listen carefully to the evidence of the security guard from the apartments. He was the only one with "no axes to grind", he said.

The trial continues.