A former boxer has been found guilty of using a samurai sword to slice open the head of a WA Police officer, in a forceful and deliberate blow a court heard was intended to kill.

Key points: Senior Constable Andrew Swift was off work for about a month after being injured

Senior Constable Andrew Swift was off work for about a month after being injured Milos Radovic had been tasered but it was ineffective in stopping the attack

Milos Radovic had been tasered but it was ineffective in stopping the attack Radovic claimed the injury he caused was accidental, but the jury disagreed

Milos Radovic, 46, was convicted of attempting to murder Senior Constable Andrew Swift outside the home of his ex-wife and three children in the southern Perth suburb of Rockingham on July 19, 2017.

Senior Constable Swift and another officer had been called to the scene after a report of a disturbance involving Radovic, who was the subject of a violence restraining order taken out by his wife.

In his evidence, Senior Constable Swift said when he arrived, Radovic was walking towards him holding something above his head.

Senior Constable Swift was injured in the attack in July 2017 but his scars have since healed. ( Supplied: WA Police Union )

He said he discharged his taser when he saw Radovic had a sword, but it was ineffective in stopping the attack.

Senior Constable Swift said Radovic continued to come towards him and brought the sword down towards him in "a chopping motion — akin to someone chopping logs".

He said he felt pain on the top of his head and his vision went black for a moment, before he took hold of Radovic and tasered him again.

Radovic said he had the sword because he wanted to speak to men who he thought had guns. ( Facebook: Milos Radovic )

They wrestled on the ground before Radovic was subdued.

Radovic was later found to also have a knife on him.

'An unfortunate series of events', officer says

Outside court, Senior Constable Swift — who was off work for about one month due to his injuries — said he was "glad at the outcome" and felt a sense of relief.

The samurai sword on the ground at the scene of the incident in Rockingham. ( Supplied: Supreme Court of WA )

"It's been a long time, 14 months waiting for this verdict," he said.

"I don't feel anything towards him personally, it's just an unfortunate series of events.

"Hopefully he just stays away for a long time, both me and his family can get on with life."

The officer was asked what he was thinking when he continued to try to stop Radovic, despite being hit in the head with a sword.

"Training. I just did what I was supposed to do, what I was paid to do, what I needed to do," he said.

Emotional scars still healing

Senior Constable Swift said while his physical scars had healed relatively rapidly, he was still recovering.

Senior Constable Swift, speaking alongside WAPU president George Tilbury, said he was just doing his job when he was attacked. ( ABC News: David Weber )

"The internal healing process is still going on emotionally. Physically, probably about three months or so," he said.

"But yeah, the emotional scars are still there."

WA Police Union president George Tilbury said he was pleased the charge had been upgraded to attempted murder, saying it was an "extremely serious" incident.

"It was a deliberate, vicious attack on a police officer, and that is totally unacceptable and should never be tolerated," he said.

"There should be a specific offence in the statute that provides a maximum mandatory penalty and we believe it should be life imprisonment."

Defence argued Radovic couldn't control his body

Speaking during the trial, state prosecutor Justin Whalley described the blow as forceful and deliberate, and said Radovic had intended to kill.

In addition to the samurai sword, a knife was found in Radovic's sock. ( Supplied: Supreme Court of WA )

The court was also told that Radovic had been heard saying "I want to kill you all".

But defence lawyer Helen Prince said it was her client's case that he had not intended to kill the officer.

She said Radovic was angry not at the police, but at members of his wife's family, and that he struck Senior Constable Swift as a result of having "a muscle spasm" after being tasered.

"He was not in any position to control his body actions, let alone the sword," Ms Prince said.

Giving evidence in his defence, Radovic, who was a FIFO welder on pipelines before his arrest, said the injury he caused was accidental.

Standing in the dock and moving his arms, he claimed the taser caused him to move in a "flow motion", from holding the sword with the blade down to holding the weapon in front with two hands.

He told the court that Senior Constable Swift "clashed into the sword" and knocked it out of his hands.

Radovic claimed incident went 'pear-shaped'

Radovic said "it happened so fast" and he did not intend to hurt Senior Constable Swift.

Constable Andrew Swift was treated in hospital after being struck with the sword. ( Supplied: WA Police )

He also told the court he had the sword with him because he wanted to speak to men who he believed had guns.

When Mr Whalley asked him if he thought he might deflect bullets with his "magic sword", Radovic said "maybe", before saying "I'm not a superhero".

"Everything went wrong, pear-shaped … I screwed up," he told the court.

In his summing up, Mr Whalley told the jury that five witnesses had seen Radovic holding the sword with his hands behind his head, and the blow was not the result of "unwilled contact".

He said Radovic was prevented from continuing his attack by the actions of Senior Constable Swift.

Justice Bruno Fiannaca said he had a concern about Radovic's mental state at the time of the offence, and wanted a psychiatric or psychological report before sentencing on January 15 next year.