Heavy rain and damaging winds are set to hit south-west Western Australia as an intense low-pressure system moves across the state.

Wind gusts of more than 100km/h and isolated rainfall totals of up to 100mm are possible across Sunday and into Monday.

The premier, Mark McGowan, said the severe weather comes after a challenging week with parts of the state enduring a five-day lockdown because of a coronavirus outbreak, and devastating bushfires in the Perth hills.

The Bureau of Meteorology said parts of the midwest Gascoyne, Perth, the south-west, lower south-west and the Great Southern region would feel the brunt of the severe weather.

Areas that may be affected include Bunbury, Manjimup, Margaret River, Walpole, Yanchep and the Perth metropolitan area.

It comes after “once-in-10-year” floods developed over the Gascoyne region on Saturday – aerial shots showed parts of the region covered by water with just the tops of trees and buildings visible.

McGowan said he had been told the region had not had such significant flooding since 2010.

On Sunday, the bureau said the low-pressure system was 80km south-west of Geraldton.It is expected to pass west of Perth on Sunday evening before crossing the south-west corner during Monday morning.

Tides are also likely to be higher than predicted along the west coast north of Augusta with the potential for flooding of low-lying coastal areas. Flood watches and warnings are current for river catchments across the Kimberley, Pilbara, Gascoyne and central west districts.

The heaviest rainfall recorded to 1am on Sunday included 76mm at Hill River Springs, 74mm at Moora, and 64mm at Lancelin East.

The highest wind gusts were 100km/h at Gooseberry Hill and 94km/h at Bickley.

Since 9am on Friday, emergency services have responded to more than 83 calls.