Australia is competing against BP-backed Indonesia and ExxonMobil-backed Qatar to supply three million tonnes of gas per year to China's first LNG terminal at Guangdong.

"Price is not the only thing that matters," the PM said on the eve of his trip. "It is also security of supply which is so very important and the experience and the skill that has been accumulated over the years."

Success could pave the way for Australia to become a major long-term energy supplier to China as economic development fuels demand for gas, oil and coal.

While Trade Minister, Mr Mark Vaille, said last month he expected China to make a decision "sometime in late May", Shell Australia boss, Dr Alan Parsley shocked other partners last week by saying he believes China will not make a decision until late June.

Dr Parsley said the delay in awarding the contract may be due to China not wanting to embarrass the Prime Minister if they decided against the Australian bid.

Before tenders closed last month, China revised its base supply quantities from 3 million tonnes a year to 3.2 million tonnes and forced a sharp price cut.