FIRST ON 7: Two killer whales have died after becoming stranded off Fraser Island, while rescuers fight to save the remaining others.

The five whales at Sheridan Flats are alive – they are four adults (6 to 7 m) and a juvenile about 4m long. The two on Bookar Island are deceased.

Rangers have been attempting to keep the whales comfortable with water and shade while waiting for the tide to rise. Conditions are also difficult, with winds 20 to 25 knots.

Local whale watching operator Peter Lynch says a marine park vessel has been sent to the area.

"[National Parks] probably have a crew of four, five or six people on it," he said.

"They are getting the terrestrial-based staff off from Fraser Island to assist with the stranding as well.

"They are working with the ones that are still alive and getting staff to the area to get ready for the incoming tide this afternoon, to give themselves the best chance to re-float those animals."

It is not known how long these whales have been stranded, but two more have been seen swimming in the area.

Killer whales follow the humpback migration to prey on the calves.