Federal Resources Minister Martin Ferguson has announced zones in the Otway basin as part of 29 new areas for exploration for potential oil and gas drilling sites in Australian waters.

Michelle Grady, from the Pew Environment Trust, said the exploration zone, covering waters from Warrnambool to Portland, included one of three Australian feeding areas for blue whales.

The noise of seismic testing could drive away the whales, which were drawn to the region by a unique mix of ocean currents and nutrients, Ms Grady said.

“This is a critical area for one of the world’s most endangered species,’’ she said.

Mr Ferguson said the release followed extensive consultation on environmental, fishing and security issues.

The permits gave companies the right to apply to search for oil and gas but not “the right to conduct seismic surveys or drill exploration wells without further rigorous approvals’’, he said.

Researcher Dr Pete Gill, director of the Blue Whale Study near Portland, said one aerial survey he conducted found 50 blue whales in the region.

Dr Gill said there was concern that seismic testing drove whales from the feeding zone, which in turn could reduce reproduction rates, but studies had so far been inconclusive.

A 2002 survey found there were between 5000 and 12,000 blue whales in the world, though Ms Grady said as few as 2000 might exist in the southern hemisphere.

The area released is the largest in more than a decade, covering about 200,0000 square kilometres — an area roughly three times the size of Tasmania.

- The Age