Banana growers hoping cyclone bends around farming hub

Banana growers on Australia's west coast are battening down as a tropical cyclone packing damaging winds bears down on a major agricultural town.

Tropical Cyclone Mitchell was about 80km north-northwest of Carnarvon on Monday afternoon and moving south along the Gascoyne coast.

The category one weather system is expected to slam into the town of about 5500 people, 900km north of Perth, during the evening, the Bureau of Meteorology says.

Carnarvon is a major agricultural and horticultural hub, worth about $100 million per year.

Known as the "food bowl" of the WA, it's located on the Gascoyne River and produces about two-thirds of the state's banana supply, along with mangoes, and other fruit and vegetables.

"A category one tropical cyclone is still a powerful weather system, and it's still likely to bring some pretty punchy weather," forecaster Angus Hines told AAP.

"Definitely a night to try and minimise your travel.

"Hopefully there's not too much fresh fruit flying around."

Damaging wind gusts up to 120 km/h and more than 100mm of rainfall leading to flash flooding is possible, along with coastal inundation in low-lying areas.

Co-op boss Doriana Mangili says banana growers are hoping the cyclone dumps plenty of rain without damaging winds.

"We have had a really hot summer, with temperatures above 48, which was very damaging for crops, so getting that beautiful rain would be amazing," the business manager of Sweeter Banana Co-operative Inc told AAP.

"But particularly bananas, they don't like winds over 100 kilometres per hour, so we're really hoping that that part stays away.

"It's just a waiting game, which is very frustrating, because you just want to see what happens and hope it doesn't happen, but we've just got to wait."

In 2015, Tropical Cyclone Olwyn destroyed the region's banana crop, which is grown on about 180 mostly family-run farms.

"This doesn't feel as if it's going to get to anything like that," Ms Mangili said.

Mitchell slid down the WA coast as a severe category three system over the weekend, before weakening to a category two on Sunday.

It brought wild weather but little damage to towns dotted along the rugged coastline and was further downgraded to a category one on Monday morning.

About 500 properties remained without power late on Monday in Karratha and Exmouth.

WA Premier Roger Cook said it was "good news" the system had been downgraded, 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."

Cyclone Mitchell is expected to weaken on Tuesday morning as it tracks over land and brings heavy rainfall to inland areas.

Communities in the Gascoyne coast, the Wheatbelt region and the Great Southern could record rainfall of between 50mm and 100mm over the next two days.

Perth will be on the edge of the rain band, but could receive up to 25mm of rain, with more than 100mm possible in some parts of the Wheatbelt.

"It really is quite a sizeable dose of rain over a really large area, as this decaying weather system moves south and southeast through the state," Mr Hines said.