MIAMI (REUTERS) - Carnival Cruise Lines has cancelled 10 more cruises aboard its ship Triumph, which was undergoing repairs after an engine fire left it stranded in the Gulf of Mexico last month, the company said on Tuesday.

The Triumph's return to service was pushed back to June 3.

The company said it also canceled two European cruises aboard the Carnival Sunshine, which had been scheduled to relaunch in April after a US$155 million (S$194 million) renovation. It is now scheduled to return to service on May 5.

Passengers whose voyages were cancelled on either ship will receive full refunds, reimbursement for nonrefundable transportation costs and a 25 per cent discount on a future cruise, Carnival said.

Carnival Corp, which owns Carnival Cruise Lines, Holland America, and Costa, among other brands, has grappled with a series of recent mishaps that prompted it to cut its earnings forecasts.

Comedians had a field day when the Triumph was adrift with more than 4,000 people aboard for five days without power to operate the overflowing toilets. The ship was towed to Mobile, Alabama, for repairs.

Carnival is in the midst of a fleetwide effort to improve fire prevention and suppression, boost backup systems and broaden the scope of hotel-type services that can run on emergency power.

Carnival said it was extending the out-of-service period for those two ships because it needed time to obtain materials and make the improvements.

"We are fully committed to applying the recommendations stemming from our fleetwide review and to make whatever investments are needed despite the difficult decision to impact people's vacations," Carnival Cruise Lines Chief Executive Gerry Cahill said.

"Moving forward, we will have the ability to source materials and schedule improvements much more expediently, thus minimising the scheduling impact on other vessels."

The Triumph sails to Mexico for four- and five-day trips out of Galveston, Texas.

The Sunshine is scheduled to operate nine- and 12-day Mediterranean cruises from May to late October, then cross the Atlantic and begin year-round seven-day Caribbean cruises from New Orleans in late November.