Carnival Corp expects the coronavirus to have a multimillion-dollar impact on 2020 earnings if the outbreak forces the cruise major to halt Asian operations through April.

The Arnold Donald-led company predicts that it will lower its full-year earnings per share (EPS) by $0.55 to $0.65, up from an earlier expected impact of $0.05 to $0.06 EPS, including guest compensation.

Carnival has 527.06m shares outstanding. That means the illness may hurt the company's full-year results in the range of $290m to $343m.

"Since the situation continues to evolve, the company is currently unable to determine the full financial impact on its fiscal year 2020," Carnival said in a statement Wednesday.

"In addition, the impact on global bookings will further affect the company's financial performance."

Carnival said it is evaluating contingency plans to mitigate the impact and will provide an update when it releases first-quarter results in late March.

The New York-listed owner of 105 ships has suspended all voyages to China, Hong Kong and Macau as part of Cruise Line Industry Association policy.

Thousands of passengers aboard its 115,900-gt Diamond Princess (built 2004), operated by its Princess Cruises brand, were detained on the ship in Yokohama following an outbreak of the illness on board.

Holland America's 82,900-gt Westerdam (built 2004) has been denied entry into most Asian ports over unfounded fears that it too has the potential to become a plague ship.

The Miami-based cruise major cancelled nine cruises on four ships operated by its subsidiary Costa Crociere after suspending operations from Chinese ports from 25 January through to 4 February.

"Travel restrictions as a result of coronavirus necessitated the suspension of cruise operations from ports in China, as was previously announced, and are now resulting in the cancellation of voyages in other parts of Asia," the company said.

"Significant events affecting travel typically have an impact on booking patterns, with the full extent of the impact generally determined by the length of time the event influences travel decisions.

"As a result of coronavirus, the company believes the impact on its global bookings and cancelled voyages will have a material impact on its financial results which was not anticipated in the company's previous 2020 earnings guidance."

Carnival said its medical experts are working with US Centers for Disease Control and Prevention and the World Health Organization to implement enhanced screening, prevention and control measures for its guests, crew and ships.

"The safety of guests and employees, compliance and protecting the environment are top priorities for the company," it said.

"The company's global team is working tirelessly to support guests impacted by voyage disruptions during this unprecedented time."