Western Australia will move to the nation's toughest COVID-19 public health restrictions despite having just 11 people in hospital with the virus.

Year three students and above will be required to wear face masks in public and home gatherings will be limited to 10 people under new rules coming into effect statewide from Thursday.

Hospitality venues will avoid being subject to a four square metre density rule but will be limited to 150 patrons.

WA on Monday recorded a further 1140 infections but none of the 11 cases in hospital are in intensive care. The state now has 5540 active cases.

Premier Mark McGowan insisted the strict new "level two" rules were necessary to manage an outbreak which the government now expects to peak at about 10,000 daily cases within two to three weeks.

He said he was hopeful they would only need to remain in place for a month.

"March will be the most difficult month Western Australia experiences in this whole pandemic," he told reporters.

"We would be irresponsible if we didn't have the most appropriate measures in place during the period where they are most required."

With the rest of the nation easing restrictions, Mr McGowan denied it was premature to tighten rules which had only been in place for one week.

He expected hospitalisations to increase "dramatically" despite WA entering its Omicron outbreak with far higher vaccination rates than other jurisdictions had.

About 63 per cent of eligible West Australians have now received their third vaccine dose.

WA Health modelling suggests the state will have almost half a million cases and 129 deaths over the next six months, with 715 people admitted to ICU.

One person has so far died during WA's Omicron outbreak.

The government had initially flagged that a four square metre density rule would be implemented at some stage across hospitality venues.

That rule will now only come into effect at the Crown casino gaming floor.

Major stadiums, theatres and cinemas will have their capacity slashed to 50 per cent while hospital visits will be banned except for spouses, parents or carers, birth partners or those allowed in for compassionate reasons.

Weddings and funerals will be capped at 150 attendees.

Mr McGowan said the revised rules would spare smaller venues such as cafes and restaurants from financial pain while slowing the spread of cases.

"While we have avoided some of the tougher measures, this will still be an impact on many operators and on people's lives and for that, I'm sorry," he said.

A new round of financial assistance for affected businesses will be announced later this week.

WA is due to also reopen its borders to vaccinated travellers from Thursday, with modelling indicating it will have a negligible impact on case numbers.

The remote Aboriginal communities of Bidyadanga and Beagle Bay have meanwhile been cleared of COVID-19 after dozens of test results proved to be false positives.

Secondary PCR testing revealed the affected people had other respiratory virus infections including the flu and rhinovirus.

The initial tests were carried out using Commonwealth-provided GeneXpert PCR machines which will no longer be used.