People already waiting at the Western Australian border will be allowed into the state after the closure deadline, as the premier flagged banning regional travel and shutting down beaches.
Long queues at the South Australian border are "unprecedented" and Premier Mark McGowan has urged people to be patient, promising restrictions will not be imposed on anyone already at the border.
"If you are a tourist wanting to come to WA, it's too late, please don't come," Mr McGowan told reporters today.
Exemptions to the 14-day isolation rule will only be made on compassionate grounds and for essential workers.
Mr McGowan said interstate travel must be avoided, adding restrictions on travelling between WA's nine regions would be announced soon.
He also warned beaches would be closed if people did not practice social distancing.
"I don't want to be doing this, but if we have to protect people from themselves on our beaches, then we will," Mr McGowan said.
He said the priority was protecting the elderly and indigenous communities.
"This is pretty extreme but this is the process we are now going through," Mr McGowan said.
"Stop your holidays, stay home, just do your essential stuff."
Mr McGowan also said another stimulus package was coming.
Optus Stadium has become a coronavirus emergency response centre for police.
Meanwhile, Australian Border Force and WA Police Force officers remain at Fremantle Port ensuring no one disembarks from MSC Magnifica while the cruise ship refuels and reprovisions before departing for Dubai at 6pm.
Some crew were spotted wearing masks.
The owners have denied any of the ship's 1,700 passengers are sick, but the state government says they have provided inconsistent information.
WA's confirmed cases of COVID-19 grew by 35 today. The state's confirmed cases now stand at 175 and include two people who are in critical condition.
Six people have recovered in the state and one man has died.
Workers on Inpex Australia's Maersk Deliverer gas drilling rig off the Kimberley coast have been sent to the mainland for self-isolation as a precaution after one tested positive for coronavirus, falling ill on return to his home country last week.
A Transperth bus driver, who had travelled overseas then returned to work, has also tested positive.
"If you're sick don't go to work ... this is very regrettable," Mr McGowan said.
Perth Zoo is closing for the first time in its 122-year history, but staff will remain on-site to care for the 1,300 animals.
Australian Nursing Federation WA state secretary Mark Olsen has called for all elective surgery to stop, saying conserving personal protective equipment is critical.
