Arrow Energy's final investment decision on its Moranbah Gas liquefied natural gas (LNG) project in the northern Bowen Basin in eastern Australia will be out in late 2013, according to chief executive Andrew Faulkner.

At the same time, Mr Faulkner remained confident that its owners, Royal Dutch Shell PLC and PetroChina Co., owing 50 per cent each of the project, will approve of final investment decision.

"Momentum on the LNG project is really very strong," Mr Faulkner told reporters visiting the Moranbah Gas Project.

The estimated $20 billion project, which Shell and PetroChina bought in 2010 for A$3.4 billion (US$3.53 billion), is one of four large developments either proposed or under construction at Gladstone that will help convert Queensland into one of the world's LNG suppliers.

Arrow Energy plans to construct two processing units at Gladstone that will hold a combined capacity of 8 million metric tonnes of LNG per year for export. With plans to add an additional two trains, annual capacity hold could reach 18 million tonnes of LNG.

Mr Faulkner said Arrow Energy has already spent A$1 billion a year on the project, and "our budget next year is larger than that," noting Shell and Petrochina had committed as much as $8 billion for the two trains.

Arrow's total gas reserve is split at 40,000 petajoules in the Bowen Basin fields and 8,000 petajoules in the Surat Basin fields, according to Business Day.