Airports of Thailand Pcl (AOT) plans to invest 63 billion baht (US$1.89 billion) in the latest expansion of the country's main airport in Bangkok, as the country tries to accommodate the influx of tourists.

State-owned, AOT will invest 63 billion baht in the third expansion phase of the Suvarnabhumi international airport in Bangkok, which would bring capacity to 90 million passengers per year, Chief Executive Nitinai Sirismatthakarn told reporters.

The airport currently has a capacity of 45 million passengers, but receives 60 million passengers each year.

Construction of a second passenger terminal will cost 41 billion baht with another 22 billion needed for a third runway, the CEO said, adding that details of the project will be proposed to an environmental committee and it was hoped will receive Cabinet approval this year.

The airport is currently in its second phase of expansion which will be completed in 2020, bringing the airport capacity to 60 million passengers per year, Nitinai said.

Thailand expects tourist arrivals to reach 37.5 million this year, up 6 percent from 2017.

AOT, which manages six airports in Thailand, is also planning a fourth expansion phase for Suvarnabhumi, which would increase capacity to 105 million, Nitinai said.