The expansion will blow the budget for the oil refinery increasing total investment to $US900 million, $US180 million higher than the previous calculation. The refinery was originally estimated to cost a total $US1.3 billion.

Negotiations on the increased cost have been completed with a consortium led by France's Technip Coflexip.

The facilities will turn all the 2.5 million tons of petrol to be produced at the refinery into Mogas 92 rather than lower quality products. Oil Refinery No.1 has a designed processing capacity of 6.5 million tons of crude oil a year, half of which will be supplied from Bach Ho Oilfield and the rest from foreign firms.

Products will include the 2.5 million tons of petrol, 230,000 tons of kerosene, 3 million tons of diesel oil, 100,000 tons of fuel oil, 260,000 tons of liquefied petroleum gas and 110,000 tons of propylene.