Rare whale frees itself from QLD lagoon

A whale has mysteriously freed itself after being stranded in a lagoon on the Great Barrier Reef.

The Bryde's whale, rare for the area, was first spotted by a tourist on a scenic flight over Elford Reef, near Cairns in June.

After several failed rescue attempts by wildlife officers, the mammal found its way out of the lagoon and back into the ocean.

Authorities believe it swam away sometime in the past few weeks.

"There was actually no physical impediments at any stage of the tide to stop it getting out so it was choosing to be there," Mark Read from the Great Barrier Marine Park Authority said.

"We don't see many of them. We get a report or two per year."

Mr Read believes the whale may have been unwell with photos indicating it was a "bit skinny".

It was last seen in the lagoon on July 18.

The Great Barrier Marine Park Authority sent a boat to check on the whale on August 4 but it had disappeared.