A safety audit conducted after the deadly Grenfell Tower fire in West London in 2017 has revealed cladding needs to be changed at Fiona Stanley Hospital, King Edward Memorial Hospital, Rockingham General Hospital and Royal Perth Hospital.

Health minister Roger Cook said it would be a "fairly extensive remedial exercise" to replace panels at the relatively new Fiona Stanley facility, starting as soon as possible, although there was no firm time frame.

"We're still getting on top of exactly the extent of the cladding that's related to Fiona Stanley Hospital," he told reporters on Tuesday.

Mr Cook said he probably would not reveal publicly where cladding had to be replaced at the site.

"Obviously there are some security fears in relation to the combustible cladding," he said.

The minister said while the actions of the state government had been prompted by the Grenfell Tower disaster, the situation in Western Australia was entirely different.

"We have extensive and highly sophisticated fire and safety process and mechanisms in place," he said.

"This doesn't represent a risk to the public or to the patients."

Premier Mark McGowan said the work would be done "whatever it costs".

Opposition health spokesman Sean L'Estrange said the government needed to commit to providing extra funding for health in the forthcoming budget to remove non-compliant cladding at all sites.

"What we don't want to find is that the minister is going to pull money from within the already reduced health budget," he said.

Australian Associated Press