Storm destruction: Rockingham, Mandurah battered

Rockingham, Mandurah and surrounding areas have been battered by severe thunderstorms as a strong cold front passed across the south-west of the state.

The wild weather set in around 8.30am on Wednesday with the worst passing through the southern suburbs just after 9am.

Trees have been uprooted with many falling onto powerlines, while fences have been blown down and tiles ripped from roofs.

There has also been reports of a tornado passing through part of Rockingham but the Bureau of Meteorology said they are yet to confirm this.

"The Bureau of Meteorology does not at this stage have direct evidence of a tornado having occurred. We will share information as it comes to hand," a Bureau spokesperson said.

"Many severe thunderstorms carry with them a slight chance of tornado development. Predicting tornadoes is difficult and specific warnings are only issued if signs consistent with tornadoes occurring are visible on radar or direct observations are received."

Rottnest Island recorded wind gusts of 128km/h, Garden Island recorded 113km/h gusts and Mandurah 70km/h.

Emergency services have answered more than 70 calls for help since midnight, while several suburbs in the City of Kwinana lost power.

A severe thunderstorm warning has since been cancelled but a separate severe weather warning remains for a large part of the state's south-west.