A sixth diver was spared from death on an expedition to explore caves in the Maldives that killed five others because she did not enter the water, it has emerged.

The woman, a student at the University of Genoa, stayed on board the yacht as her fellow researchers fatally descended to the sea floor in Vaavu Atoll on Thursday, Italian newspaper La Repubblica reported.

It is unclear why she chose not to dive, but the survivor is now heading back to her family in Italy.

Her diving companions, all Italian nationals, never resurfaced and were declared dead. So far, just one body has been located in caves 200ft below the surface.

Victims include 51-year-old marine biologist Monica Montefalcone; her 22-year-old daughter, Giorgia Sommacal; Muriel Oddenino of Turin; Gianluca Benedetti of Padua and Federico Gualtieri from Omegna.