(CNN) -- Authorities launched a search Thursday after two passengers went missing overnight off Australia's eastern coast.
The 30-year-old man and 26-year-old woman were reported missing when the Carnival Cruise ship Spirit docked in Sydney on Thursday morning, CNN affiliate Seven Network reported. The first clue came when they didn't claim their luggage.
Police, who have examined onboard video, believe the couple went overboard about 150 kilometers (93 miles) off Foster, New South Wales.
"We believe that they were up mid-deck, which is halfway up the side of the ship, which is quite a way to fall," said Detective Superintendent Mark Hutchings of the New South Wales Police Marine Area Command.
The couple was sharing a cabin and traveling with family and friends on a 10-day Pacific Island cruise.
Despite the 220-kilometer (135 mile) distance from Foster to Sydney, police said they remain optimistic
"It's game on and we are going to be pulling out all stops to try and find these people," Hutchings said.
These developments are the latest in a series of high-profile incidents involving the cruise line.
In February, an engine room fire left the Carnival Triumph adrift in the Gulf of Mexico, with passengers reporting overflowing toilets and human waste running down the walls in some parts of the ship.
On a March cruise, the Carnival Dream lost power, and some toilets stopped working.
CNN's Tina Burnside and Ric Ward contributed to this report.