Residents in Western Australia's midwest and Gascoyne regions are being urged to evacuate if their property is not cyclone-ready amid warnings of major destruction.
Tropical Cyclone Seroja is forecast to make landfall from Sunday afternoon and extend southwards through Monday as a category 2 cyclone, meaning wind speeds of 100km/h near the centre with gusts up to 140km/h.
South of Coral Bay down to Lancelin is the zone of concern with Geraldton and Denham likely to be the hardest hit.
The warning extends inland to the shires of Northampton, Chapman Valley, Morawa, Greater Geraldton, Mingenew, Three Springs, Perenjori and the townsites of Mullewa, Coorow and Carnamah.
"We hope we can get through the next few days without loss of life," Emergency Services Minister Reece Whitby said on Saturday afternoon.
Buildings in the midwest, unlike the northwest of the state, are not built for cyclones, including structures in Geraldton, which has not seen cyclonic conditions for decades, he said.
Mr Whitby said that every government agency was preparing to respond to what could be a "very significant and devastating event".
People in tents, caravans or other unstable accommodation are urged seek shelter with friends or at evacuation centres.
An evacuation centre with a sleeping capacity of 1000 people has been set up at Port Dennison, with more centres to be established.
Bureau of Meteorology senior meteorologist James Ashley has described the pending weather event as "rare" and "dangerous", warning it will be accompanied by destructive wind and intense rainfall leading to serious flooding.
Tropical Cyclone Odette, which earlier prompted the evacuation of people on islands or at sea off parts of WA's northwest coast, will be "completely absorbed" by Seroja, Mr Ashley said.
Department of Fire and Emergency Services Deputy Commissioner Craig Waters implored WA residents in the cyclone's path to stay aware of weather updates.
"If you're not fully prepared then you need to leave now," Mr Waters said.
The damage potential to buildings could be in the thousands, he said.
The weather system creating Tropical Cyclone Odette has weakened but a period of "strong to gale force" winds is possible during Saturday afternoon and evening.
The cyclone will continue to weaken as it moves southwest throughout the day, remaining offshore from the west coast.
Residents between Exmouth and Coral Bay have been warned their properties could be damaged.
Rivers likely to flood include the Wooramel, Murchison, Greenough and Avon rivers and the Yarra Yarra Lakes District.
There is a blue alert for people south of Coral Bay to Lancelin.
Multiple nature reserves are closed in WA, including Karda Reserve, Wanagarren Nature Reserve, as well as national parks at Kalbarri, Francois Peron, Houtman Abrolhos Islands and Dirk Hartog Island.
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