'Dodged a bullet': cyclone weakens as it nears coast

A tropical cyclone bearing down on Australia's west coast has been downgraded to a category one system after communities "dodged a bullet".

Western Australia's North West Cape has been tested by Tropical Cyclone Mitchell with more than 200 homes losing power as the storm hugs the coast before it is expected to make landfall on Monday night.

Cyclone Mitchell edged past Exmouth and was heading toward Carnarvon on Monday, the Bureau of Meteorology said.

A cyclone emergency has been issued for the Ningaloo and Gascoyne coasts.

Tiny resort town Exmouth - home to fewer than 3000 permanent residents - has emerged with minor damage as the system heads south.

The clean-up is already under way after gale-force winds rocked the town overnight.

"We've dodged a bullet; it could have been worse," Exmouth Shire President Matthew Niikkula told AAP.

"It was a pretty wild and woolly night. A lot of bangs, a lot of noise from the wind, but we got lucky.

"A few pot plants over and a few broken branches ... no major damage. It was such an unusual system that it hugged the coast all the way down, and affected every coastal community on its way here."

WA Premier Roger Cook said it was "good news" the system had been downgraded to a category one, but urged locals to be vigilant.

"Our thoughts are now with the people of Carnarvon ... currently in the rough, general direction that Mitchell is heading so please everyone in that community, take precautions."

Carnarvon Shire President Eddie Smith was confident locals would be ready as the system approached.

"Everybody's done the right thing and got themselves organised and had a big clean-up," Mr Smith said on Monday.

"All emergency services are in place, evacuation centres up and operating."

Onslow's Beadon Bay Hotel, northeast of Exmouth, escaped with minor damage.

"We're out of our rooms. It's all good ... we're not allowed to open the pub or the bottle shop," hotel general manager Dee Egan told AAP.

"But we've got no damage."

Cyclone Mitchell is expected to weaken by Tuesday morning as it moves over land through the southern Gascoyne.

Torrential rain and gusty winds up to 120 km/h were reported along the coast east of Giralia to Coral Bay.

Residents have been warned to prepare for flash flooding and abnormally high tides along the Pilbara coast and Gascoyne region.

"We expect to see heavy rainfall and storms could lead to flash flooding, could lead to rivers flooding, and will almost certainly lead to significant road closures, which may isolate communities," senior meteorologist Angus Hines said.

Strong wind gusts could bring down trees, damage property and cause significant power outages.

"This weather system is going to be with us for a number of days as it's going to slide southwards through the interior of Western Australia as a weakening, decaying weather system between Monday and Wednesday," Mr Hines said.