Construction will begin this year and take until 2029, AOT said in a statement, adding the expansion would increase its handling capacity from 30 million passengers to 40 million per year.

The project can "increase national income as a whole such as income from tourism, income from service sector related to tourism," AOT said. The statement said the investment included 12 aircraft parking stands and 11 jet bridges.

AOT said it would use operating cash flow for the investment.

The state-owned firm operates six international airports in Thailand, including the country's main Suvarnabhumi Airport, which can handle 45 million passengers annually.

($1 = 34.1000 baht)

(Reporting by Chayut Setboonsarng; Editing by Ed Davies)