Twenty-three travellers from New Zealand, including a child, have flown into Perth overnight despite Western Australia not being part of the Federal Government's travel bubble arrangement.
Premier Mark McGowan announced the development earlier today, stating 25 travellers had arrived, but a WA Police Force spokesperson revised the number to 23 this afternoon.
All bar one of the New Zealand arrivals remain in hotel quarantine, with the child traveller in a "quarantine arrangement" with a family member.
It follows 17 people flying from Sydney to Melbourne shortly after arriving from New Zealand, in the wake of the travel bubble arrangement coming into effect on Friday.
Up to 55 New Zealand arrivals are now believed to have landed in Victoria since the bubble began.
Mr McGowan described the situation as "fluid" and said the State Government was "doing our best to manage it".
"We would prefer better management of these arrangements, but this is something that happened that was outside of our control," he said.
Mr McGowan said the passengers had been detected through the Government's G2G app, adding it was "not an ideal situation".
"Our system has worked, we've managed to pick these people up and put them into quarantine.
"It would just be great if [the Federal Government] were to better assist us in managing these things with appropriate information being provided to the State Government about people who might be catching flights across state borders."
In a statement, Opposition Leader Liza Harvey said the Premier should "stop playing politics" over the hard border.
"[Mr McGowan] should show more compassion for stranded West Australians who want to reunite with their families in time for Christmas," Ms Harvey said.
"There are plenty of vacancies in Perth hotels in the city to accommodate more returning travellers.
Mr McGowan said a key part of that information would be passenger manifests for incoming flights.
He said the State Government had been asking airlines to supply these for years to control organised crime, but that they would now serve an even more important purpose.
"Those manifests would now be far more helpful in monitoring and controlling people who might come in who may well be from overseas or may well be COVID-positive."
The State Government is considering whether the New Zealand arrivals will be sent back, with that decision to be based on their personal circumstances.
In a statement, a Federal Government spokesperson said passengers were advised to check the entry requirements for other states upon arrival in Australia.
"Airlines must provide passenger records to state authorities if requested for contact tracing."
The revelation follows yesterday's announcement two crew members on board separate cargo ships had tested positive for COVID-19 after arriving in WA.
One of the positive cases was a crew member from the Al Messilah, a livestock ship docked in Fremantle.
Mr McGowan said the man was in hotel quarantine under supervision and the rest of the 52-person crew remained on the ship.
No livestock were being loaded at this point in time, Mr McGowan added.
The other crew member is on board the iron ore carrier Key Integrity, which is docked in Geraldton.
The Key Integrity is due to sail from Geraldton to Fremantle, arriving on Monday morning.
Mr McGowan said it was "much easier" to manage the ship in Fremantle, due to its proximity to quarantine facilities in Perth.
The two positive crew members along with an international worker who was in hotel quarantine after arriving in WA bring the state's total COVID-19 cases to 714.
There are now 20 active cases in WA.
The Premier said while the spread of COVID-19 by seafarers was a global issue, the Philippines posed a "major problem".
"I feel sorry for Filipino crew members," Mr McGowan said.
"They work hard, they basically support commerce around the world, they're not highly paid.
"But clearly, the quarantine arrangements in the Philippines are not working and so the Commonwealth needs to take international action here.
"We'll look at what we can do to make sure that we can prevent this happening in the future, but Commonwealth action with international forums and also with foreign governments is very important."
The Premier said the Federal Government needed to act quickly.
"What I'd say to the Commonwealth is & please resolve it before more extreme action needs to be taken," Mr McGowan said.
"At some point in time, we may have to say ships going through certain ports can no longer come into Australian ports.
"But it would be better if those countries put in place appropriate testing regimes and quarantine arrangements before ships sail."