The committee, chaired by Thai Prime Minister Prayuth Chan-ocha, chose a joint investor for the public-private partnership that required the lowest amount of investment from the government, the Eastern Economic Corridor Policy (EEC) office said in a statement.

The government's decision came in following months of negotiations after CP and 12 other companies jointly submitted a bid for the $6.8 billion project last year.

The rail link will connect Thailand's main international airport Suvarnabhumi to low-cost carrier airport Don Muang and U-Tapao airport in eastern Thailand.

The proposal will be sent for cabinet approval on May 28, EEC Secretary-General Kanit Sangsubhan told reporters.

The high-speed train project is slated to be completed in five years, and will be operational for 45 years under the partnership, according to the EEC portal.

The EEC project, worth $45 billion, is the centrepiece of the government's policy to boost investments in hi-tech industrials, as it transitions from those reliant on cheap labour.

The goal is to make the east a centre for hi-tech industries such as robotics and electric vehicles as well as a regional hub for aircraft maintenance.

The EEC managed to draw 297 billion baht (7 billion pounds) in promised investment in 2017.

CP is headed by Thailand's richest man, Dhanin Chearavanont, who has a net worth of $16.5 billion, according to Forbes latest estimates.

CP, not known for its expertise in rail engineering, had previously said its consortium and strategic partners include China's CITIC Group Corp, China Railway Construction, South Korea's Hyundai, Germany's Siemens, Italian-Thai Development Pcl and Japan Bank for International Cooperation.

Dhanin's businesses include pork and poultry farms in CP Foods Pcl and convenience stores in CPALL Pcl. Other interests span from a stake in Ping An Insurance Group, telecommunications, real estate and partnerships with Chinese auto-maker SIAC Motor Corp and Japan's Itochu Corp.

(Reporting by Chayut Setboonsarng and Panarat Thepgumpanat, Editing by Sherry Jacob-Phillips)