Police are investigating after a woman died while snorkelling on the Great Barrier Reef. The 76-year-old died in waters off the coast of Cairns on December 5. The investigation is in its early stages and details are limited, Queensland Police said in a statement. "However police are not treating the death as suspicious," the statement said. "It may be some time before police can confirm the identity of the woman and notify their next-of-kin." Police and investigators from Work, Health and Safety will prepare a report for the coroner. It's the second death in a matter of weeks on the Great Barrier Reef, after a 71-year-old South Australian man died while snorkelling on a reef tour on November 20. Queensland Premier Annastacia Palaszczuk said after the incident a thorough review would be conducted to "ensure it [would] never happen again". Anyone with information for police can contact Policelink online at www.police.qld.gov.au/reporting