Foreign companies are competing for an estimated $2 billion power and water project in Qatar and will submit proposals for the plant by the end of July, sources said.

The Ras Laffan C independent water and power plant project will be the biggest in the country with a generation capacity of 2,600 megawatts and 55 million gallons a day of water.

International Power, Marubeni, Suez and AES lead four consortia that have been pre-qualified, the sources said.

Qatar wants to triple electricity output from about 3,500 megawatts in 2006 to meet soaring demand driven by population growth and industrial diversification.

Technical and commercial proposals are due by 29 July on the project, one of the sources, an executive at Qatar's General Electricity & Water Corporation, said.

'HSBC has been appointed to assist in the assessment of bids and a technical adviser has been appointed,' the executive said.

The winning consortium will take a 40 per cent stake in the company with the remainder likely to be split between Qatar Petroleum and Qatar Water & Electricity Co.

Unlike previous power and water projects in the region, the developer will not be responsible for the financing.

'Financing will be put together by the local partners,' a bank source said. 'They felt they could get a better deal if they handled it separately.'

More governments in the world's top oil exporting region are turning to private sector partners to meet demand for power and water, which are surging in tandem with economic growth.

Saudi Arabia, the world's largest oil exporter, plans to spend $51 billion to increase generating capacity by 60 per cent by 2015 and wants the private sector to make up at least 25 per cent of the increase.