A disabled cruise ship will spend an extra 10 to 12 hours at sea without electricity, air conditioning or toilet facilities because of a row over tugs, a Seychelles minister says.

Joel Morgan said a French fishing vessel that was first to respond to the drifting liner refused to give way to faster tug boats.

He said the Costa Allegra likely would have arrived in port on Wednesday night local time if the tugs had been allowed to take over.

Instead the ship is not scheduled to reach port until mid-morning on Thursday.

"The Seychelles authorities are not happy about this situation and we would have wished to get the ship into port as soon as possible in order to ensure the safety and well-being of the passengers," said Morgan, minister of home affairs, environment, transport and energy.

Morgan said that when the Seychelles tugs met up with the Costa Allegra on Tuesday, a "conversation" took place to see the fishing vessel step aside and the faster tugs put in place.

"The discussion went on for quite a while to no avail," he said.

Morgan said the Seychelles is not happy that the financial objectives of the French vessel was put ahead of interests of the passengers.

Italy-based Costa said the cruise ship Allegra would arrive at about 9 am local time on Thursday (0500 GMT)- three days after the ship lost power and began drifting in the Indian Ocean.

However, the ship's estimated arrival at port has been pushed back repeatedly, and the spokeswoman for the Seychelles president said the Costa may not arrive until noon local time.

The Allegra began drifting in the Indian Ocean after a fire broke out in its generator room on Monday.

Italy's Coast Guard said that a investigators travelled to the island of Mahe with the Italian Coast Guard to do "the first assessment" of how the fire started.

Cmdr Filippo Marini, however, said it was not a full-fledged investigation.

"This is a first assessment," Marini said. "It is not an active investigation."

A representative of the cruise ship company Costa Crociere said today that an investigation needs to be carried out before a determination is made as to whether the fire was an accident or set deliberately.

The official said that investigators from the International Maritime Authority could also investigate.

Costa spokesman Davide Barbano said that while the investigation is still under way "arson is very unlikely."

The liner is carrying 413 crew members and 636 passengers, including 212 Italians, 31 Britons and eight Americans. Four passengers are children aged three or younger.

Barbano later denied that the tow would have been faster with the two tugs.

"It was decided to continue with that (the fishing vessel) because it guaranteed the smoothest voyage for those on board," he said.