The Australian maritime safety authorities have launched an investigation into the tragic death of an elderly passenger who was left behind by a cruise ship on a Great Barrier Reef island.

The passenger, a woman in her 80s whose identity has not been disclosed, was reported missing last Saturday night. The alarm was raised following a routine check of the cruise vessel, the Coral Adventurer, which revealed she was not on board.

The woman was part of a cruise operated by Coral Expeditions, which had visited the exclusive Lizard Island resort off the coast of Cooktown in Far North Queensland earlier that day.

Despite extensive land and sea searches by rescue teams, the woman was discovered deceased on the island the next day.

In a statement, the Australian Maritime Safety Authority (AMSA) confirmed that it is conducting an investigation into the incident. The crew of the Coral Adventurer will be interviewed once the ship arrives in Darwin, which is expected to be on Sunday.

“AMSA will make an assessment as to whether there was any non-compliance associated with the passenger not being counted onto the ship and, if necessary, will take action to address them,” a spokesperson said.

AMSA said it began searching with Queensland Police after the ship’s captain reported the woman missing to authorities at 9pm last Saturday.

Coral Expeditions chief executive Mark Fifield offered his apology to the woman’s family and said the company was working with authorities in their investigations.

“Coral Expeditions can confirm the tragic death of a passenger on the Coral Adventurer during an excursion to Lizard Island in Queensland,” he said in a statement.

“While investigations into the incident are continuing, we are deeply sorry that this has occurred and are offering our full support to the woman’s family.

“The Coral team have been in contact with the woman’s family, and we will continue to offer support to them through this difficult process.

“We are working closely with Queensland Police and other authorities to support their investigation.”

Queensland Police is investigating the death, but has ruled it non-suspicious.

A report is being prepared for the coroner.