A joint Australian-French study team discovered the calving of the huge iceberg, which is about twice the size of Flinders Island, about two weeks ago.

The event is not believed to be related to climate change and is described as a one-in-50 to 100 year event.

Scientists from the Australian Antarctic Division in Hobart are tracking the movement of the new iceberg which could change the ecology of the region.

They say the gigantic tougue of ice was rammed by another iceberg which itself was 97 kilometres long.

The joint Australian - French study, undertaken at the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart, and in France, was initiated in 2007 during the International Polar Year to study the tongue of the Mertz Glacier and the calving of icebergs from it.

The study team said the Mertz Glacier had had a large crack in it for the past two decades.

"A second crack developed opposite the first in the early part of the 21st century.

"The collaboration studied whether these two cracks would eventually meet, and the processes that would lead to the calving of an iceberg," the division said.

Scientists say the future position of the two giant icebergs could affect local ocean circulation, the extent of the Antarctic sea, sea ice production and deep water formation.

They say it also has important implications for the marine biology of the region.

The Mertz Glacier flows into the ocean with a flux of 10 to 12 gigatons of ice per year.

The floating part of the glacier, which originally extended over 160km from the grounding line to the front, is now only 80km long.

The glacier tongue which protruded more than 100km from the coastline is now about 20 to 25 km long.

The new iceberg is 78 km long overall and 33 to 39 km wide with an average thickness of 400m and contains enough water for human consumption for a year.