A riot broke out at Christmas Island almost two years ago after a disagreement about a clothes dryer, a Perth court has heard.
Six Vietnamese men - Son Van Vo, Van Nhat Tran, Thai Van Tran, Van Duan Tran, Hung Van Pham and Dung Van Nguyen - are scheduled to face trial in Perth Magistrates Court, charged with rioting at the North West Point Immigration Detention Centre in September 2014.
But before proceedings formally began on Monday, footage was played in court from the alleged riot showing people throwing chairs and other items around.
Matthew Russell was the officer in charge of the Gold One compound that night and told the court he did a head count as usual during dinner.
One detainee approached him about 7pm complaining that a Vietnamese person had taken his washing out of the dryer before it was finished, so Mr Russell spoke generally to the group informing them they had to wait their turn.
An Iranian man then started screaming and being verbally aggressive, before grabbing a chair, he said.
Although the man did not hit anyone with the chair, a food fight broke out with plates also thrown around for up to 10 minutes, Mr Russell said.
Everything then seemed to calm down but there was still tension before the alleged riot happened just after 8pm.
Mr Russell said about 40 people were involved in that fight, which included "a lot of things being thrown".
After the quarrel was defused, the Iranians gave up their handmade weapons but the Vietnamese held off handing over theirs for a few more hours due to safety fears, he said.
A seventh Vietnamese man, Nhan Van Nguyen, was supposed to face trial with the others but instead pleaded guilty on Monday morning to a lesser charge of taking part in an unlawful assembly.
Nguyen, who now lives in Queensland, appeared in person and had his bail renewed ahead of sentencing on Tuesday.
Eleven Iranians have previously been dealt with by the courts for similar offences.
The trial before a magistrate is expected to formally begin on Tuesday.
