Australian authorities are probing whether an 80-year-old woman who was found dead after being left behind on a Great Barrier Reef island could have been saved. Police and the coroner launched an investigation into the death of the elderly woman who had been on the first stop of a 60-day $80,000-a-ticket circumnavigation of Australia.

The solo traveller who has not yet been identified died in “sudden and non-suspicious” circumstances on Saturday, October 25. The woman, a guest aboard Coral Expeditions’ Coral Adventurer, had been hiking on Lizard Island, 250 km (155 miles) north of Cairns on Saturday, she is believed to have been hiking the island’s highest point, Cook’s Look, which is described by the Lizard Island Resort as “challenging” and recommended for guests with “medium to high fitness and agility”. She is then thought to have broken off from the group to have a rest.

“The group continued on and boarded the vessel before realising she was not there,” a source told The Australian.

The NRMA-owned Coral Expeditions cruise ship left the island around sunset but returned several hours later once the crew realised she had failed to return to the boat.

This triggered a night-time search which was carried out across the rugged national park. Her body was discovered on Sunday, and police are investigating her death and whether she could have been saved.

The Australian Maritime Safety Authority (AMSA) stated that it is investigating and will meet with the ship’s crew upon its arrival in Darwin later this week.

A spokesperson for AMSA said it was first alerted to the missing woman at around 21:00 local time on Saturday (05:00 GMT on Friday) by the ship’s captain.

Coral Expeditions chief executive Mark Fifield said staff have contacted the woman’s family and are offering support over the “tragic death”.

“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,” Fifield said.

Ms Ayris and her partner, Matthew, who were aboard SV Vellamo anchored near Lizard Island, were listening to emergency radio transmissions sent from the Coral Expeditions vessel.

“‘They did headcounts for snorkellers (which we heard) but not for other guests on the island, it would seem,” Ms Ayris told the Cairns Post.

She added: “There was not a lot of time between when the last passengers left the beach to when they up anchored

“We even commented, ‘Wow they left fast’.”

The Coral Adventurer accommodates up to 120 guests and has a crew of 46, according to the company’s website. It was purpose-built to access remote areas of Australia’s coast and is equipped with “tenders” – small boats used to take passengers on day excursions.

Queensland police said a report will be prepared for the coroner in the “sudden and non-suspicious death” of the woman.