Coral and sea life rivalling that found on the Great Barrier Reef has been discovered in the waters south of Melbourne, Parks Victoria says.

A remote-controlled vehicle was sent to depths of 100 metres by Parks Victoria to explore deep sea life in Wilsons Promontory National Park.

Fish discovered in the deep sea at Wilsons Promontory National Park. ( Supplied: Parks Victoria )

Parks Victoria marine science manager Steffan Howe said the discovery of coral reefs and fish species followed previous research mapping the park's sea floor.

"The maps identified some amazing underwater structures very deep beneath the ocean, but we did not know what sort of marine life was there," he said.

"These latest expeditions used cutting-edge technology, including underwater video cameras and a robotic vehicle to record the spectacular marine life found in many of the deeper areas of the park for the first time."

Parks Victoria said coral discovered at Wilsons Promontory National Park was beyond scientists' expectations. ( Supplied: Parks Victoria )

The vehicle found "extensive walls, house-sized boulders, ridges and caverns" of sponges and hard and soft coral.

Fish species considered rare to Victoria were also discovered, including Australian barracuda and longsnout boarfish.

The discoveries had exceed scientists expectations, Parks Victoria said.

"The resulting footage shows that the deep reef habitats are teeming with life and are home to rich and abundant marine ecosystems that are comparable to Australia's better-known tropical reef areas," Dr Howe said.

"The extent and abundance of spectacular sponge gardens and corals is a particularly exciting find."