WA Premier Mark McGowan has hit out at the Federal Government for "undermining" the states on border restrictions, insisting he is ready bring back the hard border to other states if the Adelaide coronavirus outbreak is replicated elsewhere.

The hard border was yesterday reinstated to travellers from South Australia, who must now meet strict exemption criteria to enter WA, and complete two COVID-19 tests as part of their mandatory 14 days' quarantine.

Mr McGowan said it showed he was prepared to impose "very harsh measures, very very quickly" to protect West Australians.

However the Federal Health Minister Greg Hunt said his advice from the Commonwealth Chief Health officer and the medical expert panel, the AHPPC, was that was not necessary.

He said the response to the outbreak in South Australia was "a model of early intervention."

"So, our message to the other states is please look at the results in South Australia," he said.

"Please make sure that your response is proportionate.

"What the Commonwealth has set out is enhanced border screening is an appropriate response and that is what New South Wales, Victoria and the ACT have said."

But Mr McGowan said WA's border measures were effective and had been "verified" as legal by the Federal Court and High Court.

"This constant carping and criticism from the Federal Government is getting tiresome," he said.

"They don't get it. They haven't been here, they haven't seen how well our state is doing.

"Therefore they constantly try to undermine and criticise."

Another outbreak could see more states shut out

Mr McGowan could not say what it would take to trigger the reimposition of WA's hard border, either to selected states and territories in addition to SA, or all of them at once.

"You've got to take each case on its merits," he said.

"One case somewhere might not result in hard border. An outbreak of 15 or 20 will result in a hard border. It just depends on the circumstances."

He praised the quick response by South Australian Premier Steven Marshall, saying it was the template that would be used for any outbreak in WA.

Mr McGowan said another 480 people arrived from South Australia yesterday by road and air, in addition to more than 1,300 arrivals over the weekend.

People stranded in regional towns

Some travellers who drove across the border made it to regional towns like Norseman, Kalgoorlie and Esperance before learning they would have to complete 14 days' quarantine.

Aino Tan said her family of four was turned away from a caravan park in Esperance, and instead went to a staging area set up by the local shire at the town's oval, where they were told they would be able to stay.

"But actually last night, they rounded us up about 6/7 o'clock … and told us that that's not possible, and we have to sort our own accommodation," Ms Tan said.

"So we've done that, somehow miraculously managed to sort it out and now we are heading to a place [in Kalgoorlie] to stay for the rest of the 12 days.

"We don't have much food. We don't know when we're going to get next the food delivery sorted out, so there are a lot of unknowns."

Mr McGowan said WA Police were doing their best to help travellers find suitable accommodation.

"The police commissioner I know is working on that to make sure people are accommodated in ways that keep them and us safe," he said.

WA Health Minister Roger Cook said if people were having trouble finding a suitable place to stay, the Government had a list of hotels, mostly in the city, that were considered "COVID safe".

WA Opposition Health spokesman Zak Kirkup said the Government should be doing more to help stranded travellers who were scrambling to find accommodation in small regional towns.

"They can't afford to isolate in one of the hotels, and there are hotels that are turning them away because they don't want any possible COVID infection risks there." he said.

"I think the Government does need to have an option to help people who have crossed the land border in particular."

There were no new cases of COVID-19 reported in WA today.