South Korea and Thailand have agreed to double the number of designated airlines on their bilateral routes as Seoul tackles declining travel demand from China, the transport ministry said Wednesday.

At the aviation talks held in Busan, 450 kilometers south of Seoul, Koo Bon-hwan, director general of the Aviation Policy Bureau at the Ministry of Land, Infrastructure and Transportation, and his Thai counterpart, Chula Sukmanop, agreed to increase the number of airlines on Korea-Thailand routes from four to eight, the ministry said in a statement.

"The talks were designed to help offset lower demand from China amid diplomatic tensions surrounding the deployment of an advanced US anti-missile system here," Koo said in the statement. 

As four additional airlines are allowed to serve the Thailand routes, more South Korean flag carriers will be able to take advantage of the extra slots, he said.

Currently, four airlines -- Korean Air Lines Co., Asiana Airlines Inc., Jeju Air Co. and Jin Air Co. -- have been officially designated carriers on the Thailand routes, a ministry official said.

Others that have served as temporarily designated carriers to Thailand, such as Eastar Jet Co. and T'way Air Co., will likely be given the right to fly regularly on the popular destination, the source said.

Air Seoul Inc. and Air Busan Co. will be able to join other airlines as officially designated carriers if they satisfy the requirements, he said.

Last year, 1.46 million South Koreans spent their vacation in Thailand, according to Thailand's tourism agency. (Yonhap)