Passengers onboard a COVID and gastro-riddled cruise ship were waiting to disembark as it docked in Adelaide on Monday.

The Grand Princess has been on an 18-day round trip to Queensland and back.

It is unclear how many people on board are affected, but the ship has capacity for 2600 passengers and 1150 crew members.

South Australian Premier Peter Malinauskas said those on board needing urgent care would be transported to hospitals in a way that was safe.

“It’s been something we’ve been monitoring pretty closely over the last 48 hours,” Malinauskas told Nine’s Today show on Monday.

“The good news is that reports that we’ve got from the cruise operators that the number of cases presenting has actually dramatically decreased over the course of the last couple of days.”

SA Health said it was up to the cruise ship operator to manage outbreaks on board, and at this stage it seemed there were few cases.

“We have been in contact with the ship’s doctor this morning. SA Health has been informed that the outbreaks have been declared over and the few remaining cases are consistent with numbers you would expect on any cruise,” it said in a statement on Monday.

SA Health earlirer confirmed the ship had docked in Melbourne on Saturday to undergo a clean. All passengers disembarked while that was done.

“As with all cruises, operators are responsible for having processes in place to manage outbreaks of communicable disease,” the statement said.

Cruise operator, Princess Cruises has been contacted for comment.

-with AAP