The state government of West Australia has finally given the green approval to the proposed $30-billion Browse gas project of Woodside Petroleum, despite green groups denouncing the project as an "environmental disaster" waiting in the offing.

WA Environment Minister Bill Marmion announced the development on Monday, noting the approval was released because the proposed development at James Price Point, north of Broome have met and addressed all the conditions as well as possible issues.

The conditions include cover improving knowledge and strengthening the protection of whales, dolphins, dugongs, turtles and sawfish, enhanced protection of dinosaur tracks and improved management of the risk of pollution from oil spills and air emissions, as well as invasive marine species.

"In reaching this agreement, I also took into account comments made by the ministers for Planning and State Development; and agencies, including the departments of Environment and Conservation, and Water; and the Shire of Broome," Mr Marmion said, noting the decision was reached after three weeks of consultative meetings with the ministers for Mines and Petroleum, Indigenous Affairs, Lands and Transport.

As expected, groups opposed to the project immediately condemned the approval released by the state of WA.

Martin Pritchard, Environs Kimberley director said the WA government "failed to properly consider social and economic impacts on Broome and the Kimberley."

"This proposal would be the biggest environmental disaster the Kimberley has ever seen," Mr Pritchard said.

"If we allow this damage to the Kimberley there's not going to be much left in 25 to 30 years for our children who come after us and we have a responsibility to look after what we've got," Nik Wevers, spokeswoman for Broome Community No-Gas campaign group, was quoted by Yahoo as saying.

The gas hub project still needs to pass the scrutiny of the Federal Government, through Federal Environment Minister Tony Burke, before any final investment decision pushes through.

"He's well aware just how inadequate the WA environmental assessments have been," Wilderness Society's WA state coordinator Peter Robertson was quoted by WA News.

"We hope he would put a stop to the project."