BHP Billiton Energy president Phil Aiken said the joint venture partners were currently focusing on a pricing review of existing LNG contracts with Japanese buyers and as such talk of expansion has been pushed into the background.

“When there is some idea about how (those contracts) are going, and with the fact that we are going to supply China in 2006… we intend to make a decision on train five,” he said.

“But I think that this is unlikely to be made until the first half of next year.”

“We see LNG as a very strategic growth product for BHP Billiton in the future and we’ll look at a number of options in that area.”

Woodside Petroleum boss Don Voelte had hoped for a decision on train five before the end of the year but faced opposition from some partners who believed more confirmed markets for LNG were required.

In the first week of July gas began flowing into the $1 billion fourth train where it will be liquefied for export from the Burrup Peninsula in Western Australia.

Woodside Energy, operator of the venture, began commissioning the train in readiness for meeting expanded production commitments this year.

First gas has flowed into the acid gas removal system – the first phase of the multi-stage liquefaction process – and is now entering the LNG train as part of commissioning.

The construction phase is all but finished with insulation of pipe and vessels being the major work still ongoing, while commissioning is nearly 90% complete.

The new train will boost LNG production capacity at the venture's onshore gas plant from 7.5 million tonnes a year to 11.7 million tonnes making it the biggest single LNG train in the world and the biggest construction project in Australian since the original North West Shelf LNG developments in 1980s and 1990s.