The cruise industry has again halted sailings in the key US market, this time until September 15.

The surprise move – some lines have indicated they intended to start sailings before this date – comes as the industry continues to work with the influential Centers for Disease Control and Preventions to get agreed health protocols to contain coronavirus on its vessels.

The voluntary suspension comes amid concern about how long many of the largest lines can maintain their businesses, with fleets of ships at anchor or in port manned by skeleton crews for safety.

Some have estimated the cost to be over US$3 million a ship a month for larger vessels, and share prices have fallen sharply. That said, most lines have bulked up cash reserves, and Norwegian Cruise Line said recently it could last 18 months without voyages.

Some lines had already announced new health protocols, and even plans to resume limited itineraries. But with cases of COVID-19 now spiking around the world – including North America – cruise operators are bowing to what looks like an inevitable longer wait.

Cruises in Australia, New Zealand and Asia are expected to face a similar long wait before they can be certain of resuming sailings.

“Due to the ongoing situation within the U.S. related to COVID-19, CLIA member cruise lines have decided to voluntarily extend the period of suspended passenger operations,” said a statement.

“Although we had hoped that cruise activity could resume as soon as possible after that date, it is increasingly clear that more time will be needed to resolve barriers to the resumption in the United States.”

The CDC has maintained a tough stance on the cruise industry, saying earlier this month: “We don’t have enough information at this time to say when it will be safe to resume sailing with passengers. Cruise lines may need to establish additional safety measures before sailing with passengers is permitted to resume. CDC will continue to evaluate and update its recommendations as the situation evolves.”

The current extension excluded small ships with a capacity under 250 persons.

Hurtigruten this week became the first to resume cruising on its coastal routes from Bergen.