A 22 year old man from Sydney had to be rescued after jumping overboard from a cruise ship in the South Pacific early this morning. The man was in the water for about 45 minutes after jumping from a restricted area on the Pacific Dawn cruise ship about 20 nautical miles from Vanuatu, a P&O Cruises spokesman said.

A member of the crew saw the man fall into the water and raised the alarm about 5am as the ship was headed towards Port Vila. A lifeboat and flares were used in the rescue effort and the 70,000 tonne ship did a complete turn to find him.

"The man was rescued quickly because of the immediate reaction of our crew. It was a textbook rescue operation and we are very pleased our passenger was returned safely," the spokesman said. The man was seen by a doctor on board the ship but was not injured.

The spokesman said the Pacific Dawn had since berthed at Port Vila where the man would disembark before returning to Australia by plane.

A Pacific Dawn passenger said nearly everyone on board had raced to the decks when the captain announced a man was overboard. She described it as a "party boat" and said she believed the man and his friends had been partying before he jumped.

The spokesman said a full investigation into the incident would be conducted and footage from security cameras was being reviewed. The ship will continue as planned on its 10-night South Pacific cruise.