Researchers claim to have mapped Australia's Coral Sea, detailing the reefs, mountains, and the canyons that exist underneath it.

A team at James Cook University, led by Robin Beaman, has produced the map which covers an area of about one million square kilometres, stretching from the outer-most limit of the Great Barrier Reef Marine Park to the Exclusive Economic Zone.

A major finding that the map details is the large number of underwater canyons in the area as well as 14 mountains, or seamounts rising at least 1,000 metres from the sea floor.

"One seamount, the Fraser Seamount, is 4060 metres high, nearly twice the height of Mt Kosciuszko, Australia's highest mountain. Surprisingly half of these seamounts have no identifying name which would be very unusual if they were found on dry land," Beaman said.

The large numbers of submarine canyons were found wherever the seafloor gradient exceeded just one degree in slope, say the researchers.

"The largest canyon in the Coral Sea, the Bligh Canyon, drains sediment from a huge area of the continental shelf extending from Cape York, the Torres Strait, and southern Papua New Guinea," Beaman said in a varsity release.

"This canyon is more than 200 km long, nearly 10 km wide and cuts about 300 metres into the seafloor," he added.

Using a combination of the latest satellite imagery to trace the shallow-water features, such as coral reefs and cays, and then sonar to map and trace the deeper-water features, the new map took more than a year to create.

"There are 41 separate coral reefs in the Coral Sea, with a combined area of about 15,000 square km and a combined perimeter length of 2,400 km. The largest reef, Tregrosse Reefs/Diamond Islets, has a huge area of 3621 square km. There are also currently 56 individual sand cays," he said.