The West Australian Government has moved to implement its harshest border restrictions yet, as it tries everything to stop coronavirus spreading within the state.

It will be the first time WA has ever closed its borders to the east.

"It won't be forever," Premier Mark McGowan assured.

"It's a temporary closure to make sure we limit the spread of the virus in WA."

WA will not allow anyone in eastern states to cross its borders unless they meet strict exemption criteria. ( Facebook: Mark McGowan )

There have been so many restrictions announced over the past few weeks, it can be hard to know what's what.

But unlike previous restrictions, this is the big one. Here's how it will affect you.

Who does it impact?

From midnight Sunday (well, 11:59pm to be precise) there will be restrictions on every person entering the state, regardless of their residency.

Police Commissioner Chris Dawson said airlines had been instructed to refuse non-WA residents the right to board flights into state.

WA Police Commissioner Chris Dawson said airlines had been told not to let people without a valid exemption on board. ( ABC News: Andrew O'Connor )

It adds to the Premier's stern message to West Australians outside the state that if want to come home, now is the time to do it.

Exemptions for this are still being finalised, but Mr McGowan said they would mirror many of the other essential travel exemptions already in place.

They include:

Health services

Health services Emergency services

Emergency services Transport, freight and logistics

Transport, freight and logistics Specialist skills not available in WA

Specialist skills not available in WA National or state security

National or state security Courts and judicial services

If you're a fly-in, fly-out worker, you'll be allowed to come into WA, but you and your family will be required to self-isolate for 14 days.

Fly-in, fly-out workers will be exempt but they will need to isolate for 14 days. ( ABC News )

But I'm from WA, can I still travel?

In short, no. If your travel is not essential, you'll risk being trapped on the other side.

While the new laws will primarily target those who aren't WA residents, Mr McGowan said the regulations must apply to everyone equally.

The Government has received constitutional legal advice that prohibits it from implementing laws discriminating people based on their home state.

So WA residents will be required to meet the same criteria as everyone else.

"If you don't come home before midnight on Sunday, you'll have to fit the criteria in order to come in," Mr McGowan said.

"That means you'll have to meet compassionate grounds, or you have to be part of an essential service."

People in WA can leave the state after Sunday, but they would need to keep in mind any restrictions their destination may have in place, such as a mandatory 14-day quarantine.

Plus, intrastate travel remains locked down

In addition to the state borders being closed, regional border closures remain in place within WA.

This means if you're travelling between two of WA's nine regions (Perth and Peel have been combined), you'll need a good excuse.

You risk a fine of up to $50,000 if you flout the new rules.

WA COVID-19 snapshot Confirmed cases so far: 661

Confirmed cases so far: 661 Recovered: 648

Recovered: 648 Deaths: 9

Deaths: 9 Total tests: 392,908 Latest information from the WA Health Department





It's even worse in the Kimberley.

Restrictions in WA's northern region escalated again yesterday, to help protect vulnerable remote populations.

Kimberley residents will be restricted within the four local government areas — which means no one will be able to leave those boundaries without a good excuse.

Those exemptions will include medical, compassionate or work reasons.

As the Police Commissioner put it yesterday:

"A person who may be at the Bungle Bungles will, from midnight tonight, no longer be able to drive across three or four districts in the Kimberley and then arrive in Broome. You must stay in that particular district."

If you're at the world heritage-listed Bungle Bungles, you won't be able to just drive over to Broome, the Commissioner said. ( Matt Brann: ABC Rural )

When will the borders reopen?

That's not clear at this stage.

The Premier has been open about the fact these restrictions could be in place for up to six months.

Mr McGowan said the Government would need to have very good evidence of a drop in COVID-19 cases to loosen any of the restrictions earlier than that.