An expedition to map remote parts of the ocean off Australia has yielded a startling discovery - a "lost world" of volcanoes where towering underwater peaks reach higher than sierras in the Andes mountain range.

Uncovered by a Commonwealth Scientific and Industrial Research Organization (CSIRO) vessel during a trip 400km east of Tasmania, the subaquatic world appears to be teeming with marine animals such as migrating whales.

According to CSIRO researchers, some of the underwater peaks are up to 3,000 meters in height, taller than the Andes' Copahue stratovolcano. Despite the seamounts' significant size, they are still remarkably well hidden approximately 2,000 meters below the ocean surface.

"The seamounts vary in size and shape, with some having sharp peaks while others have wide flat plateaus, dotted with small conical hills that would have been formed by ancient volcanic activity," Dr Tara Martin of the CSIRO mapping team said.

CSIRO say the "lost world" is undoubtedly a hotspot for marine life. A series of images have been released by the scientific organization revealing the sprawling nature of the secret aquatic world.

"While we were over the chain of seamounts, the ship was visited by large numbers of humpback and long-finned pilot whales," said Dr Eric Woehler, a marine researcher who was onboard the CSIRO ship when the discovery was made.

"We estimated that at least 28 individual humpback whales visited us on one day, followed by a pod of 60-80 long-finned pilot whales the next," he added.

Further voyages to the volcanic region are expected when weather conditions improve in November and December this year.