Western Australia had no new locally acquired COVID-19 cases and none in hotel quarantine on Monday, as up to two million residents in Perth, the Peel region and the state’s south-east neared the end of their first day in hard lockdown.

Premier Mark McGowan said there were “encouraging signs” amid efforts to halt the spread of the virus after it leaked from the state’s hotel quarantine.

He announced a review of the quarantine program, and a police probe into how the breach occurred.

He also confirmed that a second suspected case that emerged early on Monday – a patient in Perth’s Fiona Stanley Hospital – is being treated as likely shedding of the virus after a historic infection.

“The advice I have is that he is not a risk … He was in hotel quarantine in Sydney having returned from overseas, went through to PCR tests, which both came out negative,” Mr McGowan said.

“It may be what it is called a shedder of the viral load, as opposed to a spreader … We are awaiting final tests.”

Overnight, most states and territories – except NSW – closed their borders to people from the three locked down WA regions, and imposed testing and self-isolation rules on all arrivals. South Australia has gone one step further and closed its border to all of WA.

The snap lockdown came after a security guard at the Sheraton Four Points hotel in Perth’s CBD contracted the highly contagious British variant of the coronavirus, then went to more than a dozen venues over several days while infectious.

The man in his 20s is also a ride-share driver. Authorities believe he has not worked in that job since January 22, days before he is thought to have caught the virus.

On Monday, senior Coalition figures, including Home Affairs Minister Peter Dutton and NSW Deputy Premier John Barilaro, criticised Mr McGowan’s decision to lock down Perth and two surrounding regions to halt the spread of the virus.

Mr Dutton called the approach “not realistic”, while Mr Barilaro said it was “pointless”, firing another volley in his long-running interstate battle with Mr McGowan.

But the Premier said he had the backing of Prime Minister Scott Morrison and federal Health Minister Greg Hunt.

“Mr Dutton … is the Minister for Home Affairs. They have the responsibility for quarantine under the constitution. But he does not want to do that,” he said.

“Therefore, it has fallen to the states to perform the role that Mr Dutton should be performing under the constitution. So he should not be criticising when we are doing the task he should be performing.”

Mr McGowan said he urged “Mr Dutton not to be a critic”. He also returned fire at Mr Barilaro.

“Having borders helps. That’s why the Commonwealth has borders internationally, why when New Zealand had cases last week, they locked the border to New Zealand,” he said.

“Clearly borders help. I think that is staring us in the face, it’s just common sense.”

Meanwhile, in scenes reminiscent of lockdowns in eastern states, panic buying set in on Sunday, with shoppers scrambling for essential items such as toilet paper and milk.

Mr McGowan said he was “disappointed” at the scenes.

“There’s just no need for [it]. As we have always said, during lockdown people are permitted to visit the shops to pick up groceries,” he said.

“The most important thing is for everyone to remain calm, and
refrain from panic buying. It is completely unnecessary.”

People in the three locked-down regions must wear masks when they leave home. With many pharmacies already sold out of masks, the state’s police commissioner encouraged people to tie a scarf or bandana around their face while going out to buy one.

On Monday, Coles imposed limits on a host of “key staple items” at its supermarkets and Coles Express stores across WA.

Tweet from @Reuters

Shoppers will be limited to buying only one packet of toilet paper and two containers of milk. Other essential items such as hand sanitiser, pasta and soap are also restricted.

Read: Coles’ full list of restricted items

Meanwhile, Australian Medical Association WA president Andrew Miller has said the quarantine breach was predictable, and the McGowan government had ignored concerns about the regime.

“It’s incredibly disappointing that we are still running what we would describe as an amateurish quarantine system,” he said.

“These are not quarantine facilities, these are hotels.”

Dr Miller urged WA to invest in dedicated facilities not used for any other reasons, proper airborne protection – including fresh air ventilated through hotels – and supply N95 face masks to all security guards.

He also wanted guards to be better paid and banned from taking second jobs.

Empty streets and shops mark the first day of lockdown in three WA regions. Photo: Getty

Restrictions for another four days

Residents in the three affected areas must stay at home unless shopping for essentials, attending to medical or healthcare needs, exercising locally or working if unable to do so remotely.

Schools that were due to resume on Monday will remain closed this week.

Mr McGowan said 13 close contacts of the infected man had tested negative to COVID-19, 11 considered “high risk” were in hotel quarantine and 66 more close contacts were being tested. In all, 3171 tests were done on Sunday afternoon.

• See an updated list of venues of concern here

WA Health has released a list of 15 venues, mostly in Maylands but also including the Perth Convention Centre and a GP practice in Nedlands, that the guard visited between January 25-30.

The man returned a positive test on Saturday night after last working at the hotel on January 27. He first experienced symptoms on January 28.

Authorities are investigating the breach but say the guard did not enter a hotel room.

-with AAP