AMSA coordinated the search for an 84-year-old man who went overboard around 8.40 pm last night from the Sun Princess cruise ship, about 175 nautical miles east of Sydney.
AMSA tasked its Essendon based Dornier search and rescue aircraft and the Sun Princess cruise ship to the search area.
There have been no sightings of the man during the search.
CCTV footage from the Sun Princess showed the man entering the water from a height of approximately 25 metres.
Expert medical advice received by AMSA indicated the man was very unlikely to have survived when he entered the water given the height. The advice also indicated that the man would not have been able to survive in the water for an extended period of time given his age, clothing and weather conditions at the time of the incident. Sea conditions in the area were rough with 25-30 knots winds and swells up to three metres.
The search aircraft and ship have found no trace of the missing passenger.
In consultation with the Master of the Sun Princess, the operating company and the next of kin, the search effort has concluded.