Abu Dhabi: Work on the proposed Qatar-Bahrain causeway project, tipped to be the world's longest sea crossing, is likely to begin in the first quarter of 2010, a source familiar with the developments told reporters Sunday.

"The consortium of six contractors which includes Vinci from France is negotiating with the management of the Qatar-Bahrain causeway for the final design and cost. It has to be accepted by the board of directors of the Qatar-Bahrain Causeway Foundation before the project can start," William Nevel, Public Affairs Manager for Qatar-Bahrain Causeway Management, Kellogg, Brown & Root International (KBR), said.

He declined to provide an estimated cost for the project. "The cost of the Qatar-Bahrain causeway will be shared by the two countries," Nevel said.

Media reports previously estimated the cost of the two-nation causeway at $2.7 billion (Dh9.9 billion). According to one report, Qatar and Bahrain will contribute $700 million, and the remaining $2 billion will be provided through loans to be taken by the Qatar-Bahrain Causeway Foundation.

The proposed 40-kilometre causeway will be designed to carry passengers and freight by road and rail between Qatar and Bahrain.

The roadway will consist two traffic lanes and an emergency lane in each direction. The rail track will provide two sets of track for freight and high-speed passenger trains.