Worley secured the contract to rebuild Iraq's oil infrastructure in the north of the country through its 35% stake in a joint venture with US-based engineering group, Parsons Corporation.
The contract is the largest yet for Australian companies keen to share in the two billion US dollars' worth of contracts expected to be awarded by US authorities to rebuild Iraq.
Their chances were boosted last month when US President George Bush announced countries that did not support the war would be excluded from US-funded projects.
Australian Prime Minister John Howard was one of the staunchest allies of the US and its military action against the regime of former Iraqi President Saddam Hussein, contributing about 2000 service personnel to the campaign.
The win is also a boost for Worley which only listed on the Australian Stock Exchange in November 2002. In midday trade the group's shares had surged 8.2%, or 25 cents, at 3.30%.
Worley will be involved in extinguishing oil well fires, design and construction to restore infrastructure to a safe condition, general maintenance, distribution of oil products within Iraq and technical assistance in the sale and export of oil products.