Dugong kept in cage off Indonesian island

A dugong tied up by its tail in an underwater cage off an Indonesian island was reportedly being kept as a tourist attraction.

A diver posted distressing footage of the trapped animal on Instagram this week after finding it while swimming off the coast of the remote Kokoya Island.

One of the divers told animal welfare website The Dodo that the dugong was restrained so people could pose for photos with it.

"The ropes are worn and torn. The scars and the wound on her tail are so deep. It was very heartbreaking," Delon Lim said.

A younger dugong, believed to be the calf of the trapped mother, was reportedly kept in a nearby cage.

They were eventually freed by their captors, but only after social media posts alerted animal welfare authorities.

It is not known how long the dugongs were kept in the cages.