Authorities in Western Australia and South Australia have announced tough new measures that will see both states close their borders to slow the spread of coronavirus.

Key points: Anyone entering WA or SA will be required to self-isolate for 14 days from Tuesday afternoon

Anyone entering WA or SA will be required to self-isolate for 14 days from Tuesday afternoon Exemptions will apply for essential services and workers in both states

Exemptions will apply for essential services and workers in both states Popular WA tourist destination Rottnest Island is being investigated as a quarantine station

The WA Government has announced it will close its borders from 1:30pm (AWST) on Tuesday, although exemptions will apply for essential services and workers.

Interstate arrivals will be required to self-isolate for 14 days, and the border controls will apply to all road, air, rail and sea access points.

"These are extreme steps, but these are extreme days ... we all need to step up and play our part in one of the greatest crises facing our state in its history," WA Premier Mark McGowan said.

"WA is now in a war, the type of war we have never seen before."

Popular WA tourist destination Rottnest Island is being "actively" investigated as a quarantine zone. ( ABC News: West Matteeussen )

Popular tourist destination Rottnest Island, which is renowned for its quokkas, is being "actively" investigated as a quarantine zone.

"It is to make sure that people who cannot or will not quarantine, we can put them somewhere where they can get proper attention and support in which they are properly isolated," Mr McGowan added.

'There will only be exceptions for essential travel'

Commissioner Dawson said people arriving after the border has closed will have to self-isolate for 14 days. ( ABC News: Andrew O'Connor )

WA Police Commissioner Chris Dawson said those travelling by road would need to be across the border by the time the new measures come into force.

"If you are not able to make it before then — and we want people to travel very safely and very calmly — then you either do not leave, you stay where you are," he said.

"If you are intending to come over, we will be putting in measures which may require you to stay for 14 days at that location.

"We will be very clear about this. There will only be exceptions for essential travel."

Mr McGowan confirmed 30 new cases of COVID-19 in Western Australia, take the total to 120.

WA COVID-19 snapshot Confirmed cases so far: 662

Confirmed cases so far: 662 Recovered: 650

Recovered: 650 Deaths: 9

Deaths: 9 Total tests: 395,402 Latest information from the WA Health Department





The new cases include 11 men and 19 women aged between 21 and 79, with four cases reported in regional WA.

At least 17 of the new cases are overseas travellers or close contacts of travellers.

One of the new cases is a clinician from Royal Perth Hospital.

Up to 9,500 tests have been undertaken, with more than 1,100 completed in regional WA.

SA introduces restrictions in the 'interest of public health'

Earlier on Sunday, the SA Government declared a "major emergency" and announced it will establish 12 border crossings where travellers will be required to sign a declaration about their health and ability to undertake mandatory self-isolation for two weeks.

Those measures will come into effect from 4:00pm on Tuesday.

It comes as South Australia records its 100th case of coronavirus — an increase of 33 from Saturday.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 51 seconds 1 m 51 s South Australia will close its borders from 4:00pm on Tuesday.

Those who have been infected with the virus range in age from their 20s to their 70s, and none are understood to be in intensive care.

SA Premier Steven Marshall said the measures were being taken in the "interest of … public health".

"We received this advice from the chief public health officer in South Australia," he said.

"She was very clear that we've got to do everything we can to reduce the high-risk areas … predominantly from people coming across the borders for holidays.

"What we have seen in recent days is an increasing number of people who have contracted the virus from people visiting from interstate, or South Australians who have been interstate returning to South Australia."

Mr Marshall assured people who live in border communities they would still be allowed to cross into South Australia if there were no coronavirus outbreaks in those towns.

'Major emergency' supersedes previous declaration

The Government will allow exemptions from the new restrictions for what it labels "essential transport".

That includes the transport of health and medical supplies, health personnel and patients, food and commercial supply chains, health workers, travel of a relative or caregiver of a dependant person, and emergency services.

Fly-in-fly-out workers in the mining industry or national level sporting teams could also be exempt, but only if they had "approved disease control mechanisms in place".

SA Police Commissioner Grant Stevens will be brought onboard as the state coordinator. ( ABC News: Nick Harmsen )

SA Police Commissioner Grant Stevens will also be brought onboard as the state coordinator and will "assume all major responsibilities under the Emergency Management Act".

The declaration of a "major emergency" in South Australia supersedes the previous public health emergency.