The breach singles out a bund surrounding a hazardous chemicals storage tank which has not been updated to meet new conditions introduced in 2000.

Environmental lobby groups have protested against any further development of the pristine A-class environmental reserve and have said the breach is reason for close scrutiny of ChevronTexaco's environmental record during assessment of the $11 billion gas processing proposal for Barrow Island.

Conservation Council co-ordinator Rachel Siewert said the breach reinforced fears that further development on the island was not manageable.

Gorgon Joint Venture external affairs manager Peter Coghlan said that while the oil and gas projects were separate ventures it was committed to working with environmentalists throughout development of the gas project.