About 100 people on board Coral Princess, the first large international cruiser to enter the waters of the state of Western Australia (WA) in two years, tested positive for COVID-19, local media reported.

The cruise ship, which has the capacity of carrying nearly 2,000 passengers, was scheduled to stop at several coastal regions of the state before returning to Sydney in November.

A WA Health spokesperson said the passengers and crew aboard the vessel had tested positive for COVID-19, the national broadcaster ABC news reported late on Monday.

"WA Health has been advised of passengers and crew testing positive for COVID-19, and this evolving situation is being managed by the vessel operator according to its ­COVID-19 plan," the spokesperson said.

WA allowed large international cruise liners to return to some port destinations from October 1 after the federal government lifted the ban on international large cruise ships in April.

But all cruise ships operating in WA are required to have a COVID-19 management plan in place, and crew and passengers will be required to be double dose vaccinated and have received a third dose, if eligible.

Under the state's current COVID-19 protocols, those who tested positive for the virus are recommended to isolate for a minimum of five days.

ABC news said a spokesperson for the company operating the vessel said a rise in COVID-19 cases aboard was being "managed effectively" in accordance with national and state protocols.