A group of Australian residents and one New Zealander have had their quarantine period extended after being caught up in a deadly hantavirus outbreak on a cruise ship.

Health Minister Mark Butler announced on Thursday the six people who have been in isolation at the National Resilience Facility in Western Australia since mid-May after three fellow passengers died of the virus will remain there for longer.

The group will stay in quarantine for the full 42 days, as recommended by Australian health officials and the World Health Organisation.

“The passengers have been informed about the advice and the decision of government,” Butler said in Canberra.

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

An order under the Biosecurity Act has remained for three weeks and was extended ahead of its expiry date of June 5.

About 23 countries have quarantine arrangements for cruise passengers who have returned.

Butler said there have been two additional reports of hantavirus infections linked to the ship.

A crew member from the cruise ship, the MV Hondius, in the Netherlands has tested positive. A passenger in Spain also has the virus.

Butler said this confirmed the risk of transmission after disembarkation has not passed.

Earlier in May, a cluster of cruise ship passengers was reported to have contracted severe respiratory illnesses after it departed Argentina on April 1.

Three people have since died.

-AAP