TAIPEI Beijing could resort to military conflict with Taiwan to divert domestic pressure if a slowdown in the world's second largest economy threatens the legitimacy of the Chinese Communist Party, Taiwan's Foreign Minister said.

As Taiwan's presidential elections approach in January, China has stepped up a campaign to "reunify" with what it considers a wayward province, wooing away the island's few diplomatic allies and flying regular bomber patrols around it.

In an interview with Reuters, Taiwan's Foreign Minister Joseph Wu drew attention to China's slowing economy amid its bitter trade war with the United States.

"If the internal stability is a very serious issue, or economic slowdown has become a very serious issue for the top leaders to deal with, that is the occasion that we need to be very careful," Mr Wu said on Wednesday.

"We need to prepare ourselves for the worst situation to come... military conflict."

China's economy, though still growing, is expected to slow to a near 30-year low this year, underscoring a stiff challenge for Beijing in stepping up stimulus to keep up growth that has been fundamental to the Communist Party's political legitimacy.

Mr Wu said the economic situation in China was "okay" at the moment, but urged other countries to watch for what he saw as problems there, such as unemployment and popular discontent.

"Perhaps Xi Jinping himself is called into question of his legitimacy, by not being able to keep the Chinese economy growing," Mr Wu said, referring to China's President.

"This is a factor that might cause the Chinese leaders to decide to take an external action to divert domestic attention."