Western Australia records 24 new COVID-19 cases, including one mystery infection

Western Australia has recorded 24 new COVID-19 infections overnight, as the Bunbury cluster continues to grow.

The day's caseload is an increase on yesterday's 15, with nine new infections attributed to the expanding Bunbury cluster.

WA Premier Mark McGowan said the remaining cases are all located in Perth, and of those, one has an unknown origin.

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Mr McGowan said the new infections highlighted the need for Western Australians to take the virus seriously, with further outbreaks inevitable.

"Please go and get tested, especially if you have been at an exposure site," Mr McGowan said.

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"Please, take notes.

"Lots of people dying in the eastern states.

"The best way to protect yourself and your family is to go in and get tested if you're unwell and isolate if you've been told to do so."

A total of 96.9 per cent of WA residents have received a first dose of a vaccine, while official figures state 89.9 per cent are fully vaccinated.

Mr McGowan said, however, he was "very confident" the state had actually reached 90 per cent by the time of his press conference.

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"We're confident we're at 90 per cent double dose over 12 across Western Australia, which is a terrific achievement," he said.

There are 99 close or casual contacts linked to the current outbreak, 73 of whom have tested negative.

All are now in isolation.

As caseloads grow by the day, attention has been refocussed on the booster shot rollout, with just 30 per cent of eligible residents having received a third jab.