A question if due process was followed was the basis in the Western Australian government's halt of the release of the Environmental Protection Authority's (EPA) approval of the $40-billion James Price Point gas project.

EPA Chairman Paul Vogel was the only one who made a recommendation on the Woodside-led project because of potential conflict of interest among the four other EPA board members. Two of them have Woodside shares, another was employed by British Petroleum which is a joint venture partner in the Browse liquefied natural gas project and the fourth worked for the Department of State Development, which is the project's proponent.

Although Mr de Vogel admitted it was not ideal for him to make a recommendation on the venture alone, he insisted that the decision-making process still had integrity. He went ahead with making the recommendation after Environment Minister Bill Marmion gave Mr de Vogel the green light.

Because of criticisms from the state political opposition, environmental groups and others against the gas hub, located 50 kilometres north of Broome, Mr Marmion issued a statement on Thursday that delayed the publication of the EPA report.

"This proposal is extremely complex and I want to ensure due process has been followed at all levels," Mr Marmion said.

He explained that while the four board members had to inhibit because of the possible conflict of interest, the Environment Protection Act lacked provisions that would give him power to appoint temporary board members.

Peter Robertson of the Wildness Society said leaving the decision in the hands of one person, when it should be made by a five-man body, mocks the whole process.

"It's certainly not how the public understands how the process is conducted.... The whole idea of having a five-person independent board is so there is the active involvement of at least three on any major environmental impact assessment process," The Australian quoted Mr Robertson.

Mr Marmion did not indicate a new date for the release of the EPA decision, initially slated Friday, June 29.

"This proposal is extremely complex and I want to ensure due process has been followed at all levels," Mr Marmion said.

Despite the delay, it is believed the EPA would still approve the application but subject to the project proponents meeting some conditions, similar to what happened three years ago to Chevron's application for the Gorgon LNG development on Barrow Island.

The state Opposition called on Mr Marmion to set aside until a solution to the uncertainty over the report is solved. They called on the state premier to insist if Mr Marmion refuses to stand aside.

"This is more than a back flip. Trust in Mr Marmion's judgment has now completely evaporated," Opposition environment spokeswoman Sally Talbot was quoted by ABC.