Laws governing police pursuits passed the Lower House of State Parliament late yesterday after the Opposition labelled them "a tragedy and catastrophe", but failed to vote against them.
The WA Police Union sought urgent legal advice yesterday after shadow attorney-general John Quigley claimed the laws put the onus on officers to prove their innocence in some circumstances.
The laws, which the union called for to protect officers from prosecution over accidents arising from pursuits, passed after Labor failed to dissent.
The legislation says it is a defence to dangerous driving charges if the accused (officer) satisfies the court they were on official duty, driving within police guidelines and it was in the public interest to be driving in such a manner.
Mr Quigley said the words "if the accused satisfies the court" meant officers had to prove their innocence, rather than the prosecution prove guilt.
"We should not be putting the onus on the police on any level to prove their innocence," he said.
Police Minister Liza Harvey stood by the wording of the legislation , saying it provided an "additional defence" on top of existing defences for the charges.
"The onus of proof has not been reversed," she said outside Parliament.
"The new defence provides an additional layer of protection to police officers and therefore it is impossible for the proposed defence to lessen any protections that are currently available."
Asked why Labor was not voting against the laws, Opposition Leader Mark McGowan said: "WA Labor is not going to be seen to be on the side of rogue drivers."
A union spokeswoman said its board discussed the matter yesterday and more legal advice was being sought.
The Legislative Council will now consider the laws.