No new local cases have been recorded for a fifth straight day after a hotel security guard and his two housemates tested positive on the weekend.

Premier Mark McGowan says all of the close contacts linked to the cluster have now returned negative tests but remain in quarantine.

Authorities believe there has been no further spread of the virus.

From 1201am on Saturday, people in Perth and the neighbouring Peel region will only be required to wear face masks on public transport, at events with more than 1000 people and in hospitals, disability care and aged care facilities.

Major venues including the 60,000-capacity Optus Stadium will return to being able to host up to 75 per cent capacity crowds subject to the mask requirement.

"This is a significant relaxation on the wearing of masks which can be done safely and based on health advice," Mr McGowan told reporters on Thursday.

"The reason we are able to ease the restrictions is because of the efforts of the people of Perth and Peel. People have followed the health advice that is there to protect us."

From Saturday, people can welcome up to 100 visitors to their homes and nightclubs and casinos will reopen.

Patients in hospitals and aged care or disability care facilities will be allowed to have up to four mask-wearing visitors per day.

The requirement to continue wearing face masks in some circumstances will continue until at least Saturday May 15.

A legal requirement for hotel quarantine workers to be vaccinated against COVID-19 will come into effect from Monday.

About 30 per cent of security guards are yet to be vaccinated as WA prepares to close three "high-risk" quarantine hotels.

"I just urge all those people working in hotel quarantine who haven't had their vaccination to get the vaccination," Mr McGowan said.

"Obviously we're winding down the number of hotels so I think it will become an easier thing to manage."

Authorities believe the latest hotel outbreak may have stemmed from the guard at the Pan Pacific handling the luggage of two returned overseas travellers.

Genomic testing indicates the guard has the same US variant of the virus as the two guests who were staying on the same floor.

The guard, aged in his 20s, spent several days in the community after becoming infected.

On his days off work from April 27 to 30, he moved through the community going shopping, seeing friends and visiting Mirrabooka Mosque.

He and his seven housemates, two of whom also tested positive after working as food delivery drivers, were moved into hotel quarantine at the weekend.

Australian Associated Press