Construction giant Leighton's Middle Eastern business has won an extra $US68 million ($A66.32 million) of work building reservoirs in Qatar.

The business, Habtoor Leighton Group, has been contracted by the Qatar General Electricity and Water Corporation to build additional reservoirs at Al Duhail and Umm Qarn.

Habtoor already had a $US210 million ($A204.81 million) three-year-old contract with the corporation to build nine, new six million gallon (22.7 million litre) reservoirs and one 25-million gallon (94.6 million litre) reservoir in the same areas.

It is also building related piping and other infrastructure.