A luxury cruise liner carrying more than 300 passengers fended off an apparent attack by pirates early Saturday, the vessel's owners said.

The Seabourn Spirit was 160 kilometres off Somalia when two speedboats closed in on the vessel and opened fire with machine-guns and a rocket-propelled grenade, say witnesses.

Mike Rogers of British Columbia, among 18 Canadian citizens and permanent residents aboard the vessel, said he first realized they were under attack while he was still in bed.

"It was about 5:30 in the morning and we were awakened by the sound of what we figured out was bullets ricocheting off the side of the boat," Rogers told CTV Newsnet.

The captain came on the speaker shortly thereafter to warn passengers and the crew of the attack.

Rogers said the captain told them: "This is not a drill. We have a boat alongside that appears to be armed. Please get low to the floor and stay away from the windows."

Rogers told a Vancouver radio station that the captain tried to run one of the boats over. He said each speedboat had about four or five people on it.

"He (the captain) said he was going to do anything to stop them from getting on board."

One crew member was slightly injured by flying debris before the pirates were repulsed, said Seabourn Cruises.

"The ship's crew immediately initiated a trained response and as a result of protective and evasive measures taken the occupants of the small craft were unable to gain access to the ship," Seabourn Cruises spokesman David Dingle said.

The Bahamian-registered vessel suffered only minor damage. It was apparently hit by bullets, but it's unclear if the rocket-propelled grenade made contact.

According to Dingle, no passengers were injured, although some were in shock.

Americans and Britons were also believed to be on board the Seabourn Spirit, which was on a 16-day cruise out of Alexandria in Egypt.

The Seabourn Spirit was on its way to Mombasa in Kenya when it was attacked. The cruise will instead end at the Indian Ocean islands of Seychelles on Monday.

The crew was reportedly able to fend off the attack by using an on-board loud acoustic bang, making the gunmen believe they were under fire, the BBC website reported.

Dingle said there was no reason to believe that this was a terrorist attack. He said all evidence pointed to pirates.

The Somali coast is known to be infested with pirates, who are becoming more and more brazen.

According to the International Maritime Bureau (IMB), at least 23 hijackings and attempted seizures have been recorded off Somalia's coastline since mid-March.

Two days ago, the World Food Programme (WFP) warned that such activity had hampered delivery of relief supplies to more than 500,000 people in the region.

Due to its impact on tourism, the Seafarers' Assistance Programme (SAP) is planning to convene Monday to discuss this latest attack -- the first on a cruise ship off the Somalia coast.

Somalia has been without a functioning government since the 1991 ouster of dictator Mohamed Said Barre, and is now overrun by warlords.