Asked about the ship during parliamentary question time on Monday, Scott Morrison said NSW health authorities allowed passengers to disembark.

"The chief health officer of NSW said this was a low risk," Mr Morrison said.

Labor leader Anthony Albanese said this was effectively blaming the NSW government.

"There's a pattern there of him blaming NSW and (Premier) Gladys Berejiklian's government," Mr Albanese told reporters in Canberra.

"The truth is that the federal government are responsible for the entry into Australia."

There have been 48 confirmed cases of coronavirus among Ruby Princess passengers since they were allowed to disembark in Sydney on Thursday.

Cases linked to the ship have since emerged in Tasmania, WA and the Northern Territory.

Passengers have been urged to go into self-isolation for 14 days after authorities failed to test them for coronavirus when disembarking.

Mr Morrison said defence was now working with NSW on contact tracing.

He said the Australian government's quarantine and self-isolation requirements were announced on the ship, with disembarking passengers handed self-declaration cards.

"I note that NSW Health has stated that it undertook a full assessment of the Ruby Princess and allowed the passengers to disembark," he said.

There have been multiple confirmed coronavirus outbreaks on cruise ships across the globe, with other Australian cases linked to the recently docked Ovation of the Seas.

The furore over the Ruby Princess follows the Australian government being forced to rescue citizens off the Diamond Princess in Japan, with one Perth man later dying due to the virus.

Australian Associated Press