In what seems to be a string of bad luck for cruise lines, another tragedy has struck Carnival Cruise Lines this week.

According to authorities, an unidentified couple, one 30-year-old man and one 27-year-old woman, have been missing from Carnival's Spirit cruise ship in Australia since Wednesday reported ABC.

The couple was reportedly seen falling overboard the ship on surveillance footage from Wednesday night and could not be located on board after the ship had docked at Sydney's Circular Quay Thursday.

New South Wales State Police Superintendent Mark Hutchings said the couple fell from the ship's mid-deck, an estimated 185 miles outside of Sydney where the ship ended its 10-day journey.

"This is a tragic event at the moment, but we're holding out hope we might be able to find these people alive," said Hutchings, who said local police were alerted of the missing persons cases two hours after the ship had docked.

Police are continuing the investigation to decipher if the couple accidentally fell or if the jump was intentional. According to the Huffington Post, the ship's 600 security cameras are monitored 24 hours at day, but workers onboard did not witness any suspicious activity at the time of the couple's disappearance.

Friends and family traveling with the couple confirmed that they last saw them together on board Wednesday night reported ABC.

Carnival spokesman Peter Taylor said the company is working closely with authorities in air and water searches to locate the missing passengers.

"We have naturally been concerned since we became aware that two passengers were missing from Carnival Spirit and our thoughts are clearly with their families at this difficult time," said Taylor.

This incident is one of the many Carnival Cruise Lines had endured this year. In March, the company's ship, Carnival Dream, experienced technical problems in the Caribbean, leaving passengers stranded aboard the unmoving vessel without electricity and running water. The cruise line denied the allegations from some passengers that claimed human waste flooded the bathrooms and staterooms aboard the ship.

In February, a fire aboard Carnival Triumph left 4,200 passengers stranded in the Gulf of Mexico. One passenger reported guests were forced to live in urine-soaked quarters and were forced to sleep in the ship's hallways for a five days before being rescued.