South Korea Wednesday scrapped its plan to send a pair of supersonic military jets to a Chinese airshow next week, citing pressure from the United States.

The South's air force had planned to dispatch T-50 trainers to the November 11-16 airshow in China's southern city of Zhuhai, as part of a military exchange between the two countries, a defence ministry spokesman said.

But the plan was cancelled at the last minute following consultations between South Korea and its key military ally, the United States, he said.

"We decided to cancel our participation in the Chinese airshow after the US cited its law concerning exports and trade of key US military technology," the spokesman said, explaining that core technology used in the aircraft came from the US.

"South Korea maintains a mutual defence pact, and we need US consent about some military issues," he added.

T-50 is South Korea's first homegrown supersonic aircraft jointly developed by Korea Aerospace Industries and US defence giant Lockheed Martin.

After developing it into combat and multi-role variants, Seoul has sought to open up new markets for military exports beyond Southeast Asia, Europe and South America.

China, North Korea's sole major ally, has gradually strengthened military cooperation and exchanges with the South.

The United States, in its "pivot to Asia", has boosted its military presence in the region, a move that has alarmed China and emboldened its rivals.

China, meanwhile, has been rapidly modernising its military amid maritime territorial disputes with regional neighbours.