Businesses in Kalgoorlie would shut down because of fears of another riot if the trial of a man accused of running down a teenager was held in the city, a senior police officer has testified.

Superintendent Tony Colfer was giving evidence at an application by the accused man, whose identity is suppressed, to have his manslaughter case heard in Kalgoorlie instead of Perth.

The man is alleged to have run down the 14-year-old, who has not been named for cultural reasons, in August last year.

The death sparked riots in Kalgoorlie when about 200 people gathered in the city centre and threw rocks and bottles at the court house, cars and police.

Today in the Supreme Court, Superintendent Colfer described the riot as massive, and the scariest day he had ever worked.

He said 15 police officers were injured and 60 arrests were made, although it was just luck the injuries and damage list was not longer.

Superintendent Colfer outlined his main concerns about the trial being conducted in Kalgoorlie, including fears of another riot and for the safety of jury members.

"People are very frightened … and don't want to see that kind of behaviour in the town," he said.

"Stakeholders, business people, they will will shut up shop for the week the trial is on."

Superintendent Colfer also expressed concern about social media, saying while "things had quietened down" since last August, there were still some posts talking about crime in the city.

Under cross-examination from the man's lawyer, Seamus Rafferty, Superintendent Colfer accepted if the trial was in Kalgoorlie, WA police would do everything possible to ensure it ran smoothly, including sending extra resources to the city.

He also accepted that unlike the riot last year, police had warning about the possibility of trouble and could plan ahead to minimise any problems.

The 'mob should not win', lawyer argues

In his closing submission, Mr Rafferty said in the interests of justice the trial should be in the region where the alleged offence occurred, and while that may mean additional costs, there was "no price on justice".

He told the court "the mob should not win" and the criminal justice system should not be dictated by the bad behaviour of others.

He also said the defence considered that a viewing of the scene of the alleged offence was crucial to the case and it would be easier for that to happen if the trial was in Kalgoorlie.

"The offence is said to have happened in Kalgoorlie. The people of Kalgoorlie ought to determine the outcome this charge, in circumstances where a view of the scene was required," he said.

Threats are 'real', prosecution argues

Counsel for the state David Jubb said that could still happen if the trial was held in Perth, because the jury and all others involved, including the accused man and the judge, could be flown to Kalgoorlie and back in a day.

Mr Jubb submitted that last year's riot was "a significant event" and there were fears it would be repeated.

"There's a real threat, real concern, public anger will follow," he said.

Mr Jubb also said it would be "a difficult task to protect the jurors" and to protect the accused, who would have to be housed in the local prison where relatives of the teenager were also being held.

"We're looking at taking the trial to a place where we know there will be difficulties … Why we would want to send the trial to Kalgoorlie … when the resolution is relatively simple? Have the trial heard in Perth."

Justice Lindy Jenkins has reserved her decision.