The Perth arrival of six cruise ship passengers exposed to the deadly hantavirus is in limbo, as authorities scramble to find them a plane.

The $400 million COVID-era quarantine centre that has been sitting idle in Bullsbrook is on standby for the group, that’s been told they will need to isolate for at least three weeks.

But Roger Cook said it’s unclear when a repatriation flight will depart from The Netherlands to Perth, despite the passengers being given just 48 hours to quarantine in the European nation.

The Premier conceded the requirement for the pilot and crew to quarantine too might be a factor.

“I can imagine it would be hard to source the appropriate assets at this stage,” he said.

“Maybe there’s some reluctance on a pilot to be stuck on a plane, but I don’t think so. I just think it’s a matter of the Commonwealth working through their planning and preparation.”

Federal Health Minister Mark Butler has confirmed the three-week quarantine may be extended, and defended Australia’s stricter quarantine rules as a “precautionary” approach.

“There is an incubation period of 42 days potentially for this virus, but that incubation or the risk of transmission obviously drops off after the first few weeks,” he said on Tuesday.

“So we’ll be seeking further advice from our chief health officers.”

A French woman who tested positive for hantavirus after disembarking from the MV Hondius is now in a critical condition.

Three people have died.

But though hantavirus has a high mortality rate, it is not as contagious as Covid.

Mr Cook has described the risk to the public from the Perth-bound group - that includes four Australian citizens, a permanent resident and a New Zealander - as “non-existant”.

“Because that’s the advice from the Chief Health Officer,” he said.

“Look, we just know that those people are still in the Netherlands. My understanding is that the Commonwealth is struggling to medically evacuate them.

“They are not unwell. They are not they are not displaying any symptoms.”