A P&O cruiseship discharged 27,000 litres of waste water into the Great Barrier Reef in Australia, the country's senate has been told.

A report by the Australian Maritime Safety Authority (AMSA) claimed the dumping of food waste and grey water occurred on 26 August from the 77,000-gt Pacific Explorer (built 1977), the Guardian said.

The senate hearing was told P&O reported the spill to AMSA, but the reef park authority was not informed until 4 September.

The AMSA report found the spill happened after food waste was transferred to the vessel's galley holding tank as it ran short of space in its usual waste tanks.

This was then discharged by engineers. The report said the ship became aware of the incident late on 27 August.

A spokesperson for P&O said the company had “self-reported to AMSA that it was suspected there had been an unintentional discharge of a limited amount of pulped and sieved food waste while Pacific Explorer was off the coast of Queensland on August 26”.

“Any unintentional discharge of food waste would have been in the order of seven cubic metres,” she said.

The company said it was an isolated incident and the cruise line was cooperating with AMSA’s investigation.

“P&O Cruises is committed to the protection of the marine environment and this is supported by very strong fleet policies and operating procedures,” the spokesperson added.