Premier Mark McGowan has confirmed Perth and Peel will exit lockdown but some restrictions will remain in place for the rest of the week.

"The short three-day lockdown has done the job it was designed to do," he told reporters on Monday.

"It was a circuit breaker we needed to limit community spread and keep our community healthy."

Interim restrictions will remain in place until 12.01am on Saturday.

Schools will return and people will be free to leave their homes and travel to other regions but must continue to wear face masks.

The mask requirement applies to anyone who has been in Perth or Peel since April 17.

Indoor gatherings, including at homes, will be limited to 20 people.

Venues can reopen with the exception of the casino, nightclubs and indoor fitness centres but a four-square-metre rule and 20-patron limit will apply.

People will only be allowed to visit hospitals, aged care and disability care facilities on compassionate grounds.

The premier urged West Australians to continue using the SafeWA tracing app and to get tested if they had visited exposure sites or experienced any coronavirus symptoms.

"We need to be cautious when we come out of lockdown as the virus could still be out there," the premier said.

Two locally acquired cases have been confirmed after the virus leaked out of the Mercure quarantine hotel last week.

Authorities have identified 354 close contacts of confirmed cases and 222 have so far returned negative test results.

Out of 748 casual contacts identified, 329 have tested negative with other results pending.

More than 29,000 tests have been conducted since Friday.

The guest at the Mercure whose infection led to the outbreak had travelled to India last December to attend his own wedding.

Both he and his bride tested positive in hotel quarantine upon returning to Australia earlier this month.

Home Affairs Minister Karen Andrews defended the wedding travel exemption amid a growing war of words between the state and federal governments.

"When the exemption was granted for that individual it was absolutely in line with the criteria at the time," she told Perth radio 6PR on Monday.

"A wedding would (now) be unlikely to be approved."

Ms Andrews said travel was now only permitted to India if it was in the national interest, part of the COVID response or for medical treatment unavailable in Australia.

Genomic testing has confirmed the virus spread from the couple from India to several other guests in nearby rooms, including a Melbourne man who did not test positive until after he had completed quarantine and spent five days in the community.

A female friend of the Melbourne man also tested positive after he stayed at her house.

A second locally acquired case was detected on Saturday - a man in his 40s who had dined at the same Kardinya restaurant as the Melbourne man.

His household contacts have been cleared of the virus and 50 close contacts identified from the restaurant have tested negative.

WA's cap on international arrivals will be halved to 512 a week for the next month.

A report received by WA's chief health officer earlier this month identified the Mercure as the highest-risk of Perth's quarantine hotels due to ventilation issues.

The premier on Monday apologised for the disruption caused by the lockdown.

"I'm very sorry it had to happen," he said.

Mr McGowan has urged the Commonwealth to open air bases and Christmas Island to accommodate returned travellers, adding that it is the Commonwealth's constitutional responsibility to handle the quarantine scheme.

The federal government has said such facilities are not suitable.

Australian Associated Press