A major search and rescue operation is underway after a passenger was reported missing from a Carnival Cruise ship overnight, just hours after a woman from the same ship died while snorkelling.

Crews continue searching for a man who fell from the Carnival Splendor on Friday night near Moreton Island.

The alarm was raised after the man’s family was unable to find him and alerted staff aboard the ship as it made its way down the east coast of Queensland.

The search follows the death of a 67-year-old Tasmanian woman and passenger from the same ship only hours earlier.

Police said the woman had been found unresponsive in water near the Tangalooma shipwrecks, a popular snorkelling location with visitors, about 11.46am on Friday.

Attempts were made to revive the woman, however she was pronounced dead at the scene.

Police are investigating the circumstances surrounding her death.

“Carnival Cruise Line is deeply saddened by the death of a guest on Moreton Island on Friday,” a Carnival Cruise Line spokesperson said.

“Our Care Team is supporting the guest’s family during this difficult time.”

Several hours later, a second tragedy hit the ship when a passenger went overboard.

The Australian Maritime Safety Authority (AMSA) told 7NEWS.com.au they were contacted by the Master of Carnival Splendor about the missing man.

AMSA said it is currently coordinating the search and rescue operation and has tasked its Cairns and Melbourne-based Challenger jets, five rescue helicopters from around the metropolitan Brisbane area, and six surface vessels into the area, with Queensland Police assisting AMSA with the operation.

A Carnival Cruise Line spokesperson said the two tragedies are not believed to be linked.

“Carnival confirmed on Saturday that Carnival Splendor was assisting authorities search for a guest who apparently climbed over the safety railing and jumped overboard as the ship was sailing from Moreton Island towards Sydney overnight,” The spokesperson said.

“The male guest was travelling with family who alerted the ship’s crew of a possible missing person and a review of the CCTV footage confirmed the guest’s action.”

Emergency services were contacted and have been assisting in the search for the man, about 53km east of Moreton Island, near Brisbane.

“All appropriate authorities have been alerted and Carnival will assist authorities in their investigation upon the ship’s return to Sydney,” the spokesperson said.

“Carnival’s Care Team is supporting the guest’s family and our thoughts and prayers are with them and their loved one.”