Ningaloo Reef snorkeller suffers serious injuries after being struck by humpback whales

A woman has suffered serious injuries after being struck and injured while swimming with humpback whales off the coast of Western Australia.

The 29-year-old woman was part of tour group snorkelling at the popular Ningaloo Reef on Saturday when she was struck.

Unconfirmed reports said she become trapped between two of the giant mammals, which can grow up to 19 metres, suffering fractured ribs and internal bleeding.

St John Ambulance said the woman had suffered internal bleeding and upper torso injuries "from the crush".

She was treated in the town of Exmouth before being flown to a hospital in Perth, where, as of today, she was in a "serious but stable condition".

Western Australia Police advised that other guests on the snorkelling tour – which had only been a few hundred metres from the shore when the incident happened - witnessed the incident but were uninjured.

A Western Australia Police spokesperson said work safety regulators were investigating the incident, as it had involved a charter group.

Chartered swimming with humpback whales is currently undergoing a five-year trial in the region, monitored by the Western Australian Department of Biodiversity, Conservation and Attractions (DBCA).

15 tour operators have been licensed to take groups of nine swimming with the whales, with guidance in place advising the swimmers to stay at least 15 metres from the animals.

The Department said in a statement it was "working closely with the industry and the tour operator involved to understand how the incident occurred", and that swimming with humpback whales involved "some inherent risk".

It noted that nearly 10,000 participants had swum with humpback whales since the trial began in 2016, with no previous incidents resulting in serious injuries.

Image: Humpback whales at Western Australia's Ningaloo Reef.