The West Australian premier has flagged banning regional travel in a bid to stop the spread of coronavirus as unprecedented queues crossed the South Australian border after the closure deadline.
The number of coronavirus cases in the state surged by 35 on Tuesday, including a four-year-old and 10-year-old from the same family.
The cases include five in regional WA and bring the state's total to 175.
Health minister Roger Cook said eight were passengers on the Ruby Princess cruise ship and four were on the Ovation of the Seas.
That is on top of seven other confirmed cases from those ships on Monday.
Dozens were confirmed after the ships docked in Sydney last week.
"Now you see just what an impact those two cruise ships have had nationally," Mr Cook told reporters on Tuesday.
Premier Mark McGowan promised restrictions would not be imposed on anyone already at the WA border but told tourists wanting to visit it was too late.
Exemptions to the 14-day isolation rule will only be made on compassionate grounds and for essential workers.
Mr McGowan insisted intrastate travel must be avoided, adding restrictions on movement between WA's nine regions would be announced soon, probably excluding travel between Perth and the neighbouring Peel region.
"This is pretty extreme but this is the process we are now going through," he said.
"Stop your holidays, stay home, just do your essential stuff."
Mr McGowan 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."
The premier said another stimulus package was coming.
Optus Stadium has become a coronavirus emergency response centre for police.
A TransPerth bus driver, who travelled overseas then returned to work, has also tested positive.
Mr Cook said 11 people were in hospital, four of those in intensive care.
He also announced expanding WA's testing regime, including an "aggressive outreach" program for areas where community transmission is apparent.
The regime will also include disembarked cruise ship passengers.
The criteria for COVID-19 clinics remains the same.
Elective surgery will be further reduced, with operations essentially only for urgent cases.
Mr Cook also said the shortage of personal protective equipment for health care workers was easing, with shipments flowing into Australia.
Meanwhile, Australian Border Force and WA Police officers remain at Fremantle Port ensuring no one disembarks from Magnifica while the cruise ship refuels and reprovisions before departing for Dubai at 6pm.
The owners have denied any of the ship's 1700 passengers are sick, but the state government says they have provided inconsistent information.