Australian researchers have been able to accurately establish the numbers of sea turtles at the largest nesting site of its kind in the world for the first time, thanks to drone technology.

Raine Island, off the northern tip of Australia, plays host to around 60,000 female green turtles who migrate hundreds of kilometres from the Great Barrier Reef to lay their eggs each year.

Scientists working to protect the endangered species had struggled to find the best way to keep track of the numbers of nesting turtles, but their use of drones has shown that they had been underestimating numbers by more than 50 per cent.

Their findings were revealed in a paper published this month in peer-reviewed journal, PLOS One.

Stunning drone footage released by the Great Barrier Reef Foundation on Tuesday shows thousands of turtles swimming off the island's coast.

The researchers had previously counted turtles as they landed on the beach to lay eggs - with about 23,000 counted in a single night - and by marking the creatures with non-toxic soluble paint to more easily track them in the ocean.

"Trying to accurately count thousands of painted and unpainted turtles from a small boat in rough weather was difficult," the paper's lead author Andrew Dunstan said.

"Using a drone is easier, safer, much more accurate, and the data can be immediately and permanently stored."

Their work, as part of the Raine Island Recovery Project, also includes rebuilding the nesting beaches on the remote cay - or reef - and constructing fences to prevent turtle deaths.