Analysts are projecting that the Curtis Island liquefied natural gas (LNG) project in Queensland by the British Gas Group could exceed the previously headlined cost of $US15 billion and even surpassed that of Santos' Gladstone cost estimates of close to $US19 billion.

The British group already forked out some $US3 billion to start rolling out the LNG initiative and experts said total costs could reach more than $18 billion for full realisation and prior to full operation.

Industry experts said that the projections were still exclusive of the costs set to be shelled out by the Queensland project's minority partners, the Tokyo Gas and China National Offshore Oil Corp (CNOOC).

An estimated $US1 billion construction costs were poised to be billed on the Curtis Island's two minor players though British Gas refused to confirm the exact figures as analysts waited to be tipped on the numbers, which they anticipated would probably surpassed the maximum $US19 billion set for Santos Ltd's Gladstone LNG project, also in Queensland.

Analysts were convinced that while the Santos LNG undertaking in the state was a bit smaller in size, its total cost would have a higher headline number as the company has determined to observe fixed-price contracting on the project.

They added that Santos, unlike the British group, would need to consider the likelihood of contingency costs due to the size of its Queensland LNG project, giving the Curtis Island initiative a head cost estimate of up to $US2.5 billion.

Prior to the end of the current calendar year, experts said that both the Queensland and federal authorities would approve the sale of an estimated seven million tonnes of LNG, with Origin Energy set to collaborate with US firm ConocoPhillips for pushing ahead with the planned Asia-Pacific LNG project (APLNG).

Investors should be soon advised on combined cost of the Gladstone LNG projects as Conoco chief executive Jim Mulya said that "we plan to have an announcement regarding the sale of two trains of LNG before year end," while Santos has indicated that the initial stage of its GLNG project would gain approval by 2010's final weeks.