The stand-off ended about 7am when the man at the centre of the siege, David Charles Batty, was shot with beanbag bullets, which did not harm him but subdued him enough to be arrested by police.

Opposition police spokeswoman Michelle Roberts has criticised the government for not preventing the situation.

She said Mr Batty had escaped Romily House, a secure transitional facility in Claremont, about a year ago and a warrant was out for his arrest.

Asked if it was appropriate to make political points regarding the incident, she said police on the scene had done a great job, but responsibility needed to be taken.

"This has traumatised a lot of people last evening, is a considerable use of police resources and it should not have been able to happen," she said.

"People will live with that trauma for years to come and it's because of mismanagement by this government.

"[The government was] very quick to criticise former governments on issues like this."

In June 2004, while Ms Roberts was Justice Minister, Fairfax Media reported that nine prisoners had overpowered guards at the WA Supreme Court, stole the supervisor's keys and fled before carjacking two motorists.

Despite their recapture, the breakout prompted the government to urgently reassess the security at the court and the role of the security firm responsible, which Ms Roberts said showed systemic failure.

Preliminary investigations resulted in her department resuming responsibility for court custody services to ensure public safety.

At the time, then-opposition leader Colin Barnett said Ms Roberts should be held to account for putting lives at risk as a report to the government had warned two years earlier that security was poor, prisoners could easily break out and said major building renovations were needed.

Ms Roberts denied she had been negligent in not immediately acting on the report, and said $3.5 million in funding for the works had been included in the 2004-5 State Budget.

"I think that a greater case could have been made at an earlier time for that upgrade work to happen on an earlier occasion and it simply wasn't made," she said at the time.

Police have not yet laid any charges over the incident in Bunbury.

Acting Mental Health Minister John Day has been contacted for comment.