Australian passengers who recently returned home from the deadly hantavirus-stricken MV Hondius cruise ship have been told they will be forced to remain in quarantine for another three weeks.

Earlier this month the travellers were taken to a special facility in Western Australia’s Bullsbrook, for an initial isolation period of three weeks, but health officials have recommended they now remain there for the entire 42-day incubation period.

“As a result, on the basis of accepting that advice, it’s likely an order will be made to extend that quarantine period to the 23 of June,” Health Minister Mark Butler told reporters.

“The passengers have been informed about the advice and the decision of government.”

“I’m happy to say they remain well, they have only been tested again in the last 24 or 36 hours or so and all six have again tested negative,” Mr Butler said.

“But the cases overseas and the advice not just of our public health officials but of the World Health Organisation indicate that does not mean that the risk of testing positive sometime into the future during that 42-day incubation period has completely passed.”

The four Australian citizens, a permanent resident and one resident of New Zealand have been quarantined at the National Resilience Centre, since returning on May 15, five weeks after the first death on board the MR Hondius.

Initially the six passengers were flown into RAAF Base Pearce in Western Australia and taken to a nearby facility after being placed under a three-week quarantine order made under the Biosecurity Act, which was due to conclude on June 5.

The $400 million quarantine facility at Bullsbrook, 40 kilometres north-east of Perth, was built during the COVID pandemic and completed in 2022 but had never been used for its planned use and had sat empty practically ever since.

Over the past five days, two more cases of hantavirus have been confirmed among passengers and crew who were aboard the Dutch-flagged cruise ship during April and May.

The outbreak now has 13 confirmed cases, three of which were fatal.

Several passengers remain in isolation and quarantine in various countries, including 18 Americans who are staying in a biocontainment unit in Nebraska through the end of the month.

The first new case identified late last week was in a Dutch crew member who had disembarked the MV Hondius in Spain and was being monitored for the virus.

Mr Butler said the weekend confirmation of another case confirmed that the risk of transmission of the virus “has not passed” and highlighted “how serious this virus can be”.

The Andes strain causing the current deadly outbreak is the only known hantavirus capable of spreading from person to person.