A cruise ship with an outbreak of COVID-19 among crew and passengers arrived in New South Wales today, as the state government announced a key change to its health policy.

Queensland Health said 118 people on the cruise ship Coral Princess had tested positive for the virus since it left Brisbane on Sunday. Of those cases, 114 were crew members and four were passengers.

The ship, carrying more than 2,300 guests and crew, docked in Eden on the New South Wales South Coast today, the first cruise ship to return to the city since COVID-19 shut down the industry two years ago. The ship is by itinerary scheduled to be in Sydney for a day on Wednesday.

The outbreak comes as NSW Health announced its official reinfection period was being revised from 12 weeks to four weeks, as the latest sub-variants of Omicron circulate in the community.

This means that people who develop symptoms any time after 28 days from the last period of isolation from COVID-19 may be reinfected with the virus and need to be tested.

No crew members will disembark and all disembarking passengers will be asked to first provide a negative RAT result.

Queensland's Chief Health Officer John Gerrard said 24 people with COVID had disembarked in Brisbane and were all in isolation.

The rest are isolated on board as per the state protocol.

Dr. Gerrard said the COVID protocols on cruise ships were "very adequate".

"There is a lot of detail in those protocols and requirements for the cruise industry. There's been a lot of thought by public health officials and epidemiologists ... about putting these protocols in place."

Dr. Gerrard said it was "inevitable" that there would be outbreaks on cruise ships.

A spokesman for Carnival Australia said recent screening found some crew members had tested positive and had been placed in isolation away from passengers.

A spokesman said the number of cases identified by Queensland Health were "predominantly among crew who were isolated on board in accordance with protocols that effectively supported the resumption of cruises to Australia from May".

On July 9, a passenger received a letter while on a cruise alerting him of an outbreak of COVID among the crew.

"We would like to inform you of the increased number of positive cases among crew members currently on board the Coral Princess," the letter said.

"We continue to test all crew members and isolate anyone who tests positive along with their close contacts."