A South Korean consortium has won a $40 billion deal to build and operate four nuclear reactors in the United Arab Emirates.

The South Korean group, led by state-owned utility Korea Electric Power Corp, has been contracted to ensure the first nuclear plant in the Gulf Arab region starts supplying power to the UAE grid in 2017.

The South Korean president's office has called the deal the largest mega-project in Korean history at more than six times bigger than the previous single contract.

The consortium will design, build and run four reactors with capacity to produce 1,400 megawatts each of electricity.

The contract to build the plants is worth around $20 billion.