China claims Taiwan as part of its territory and has in recent years stepped up its military presence and sabre-rattling rhetoric towards the democratic island.

The United States has stepped up military aid and weapons sales to Taiwan to counter China, but Trump said earlier this week the island "should pay" Washington for defence.

In response Friday, Taiwan's newly minted foreign minister Lin Chia-lung said Taipei took the former president's comments "very seriously".

"Everyone should have this consensus that the threat is China," he told reporters in his first briefing with foreign media since his appointment to the cabinet of Taiwan's new President Lai Ching-te.

"As far as national defence is concerned, we must rely on ourselves," he said, adding Taiwan has increased its military budget from 2 percent to 2.5 percent of its GDP in eight years.

"I expect it will continue to increase," he said, adding that the budget will go not just to purchasing more weapons but also instating military reforms.

In an interview with Bloomberg Businessweek published earlier this week, Trump had said the United States is "no different than an insurance company. Taiwan doesn't give us anything".

His comments cast doubt on the relationship between Washington and Taipei, which has steadily been strengthened in recent years.

Washington recently passed a multi-billion-dollar military aid package aimed at countering Beijing in the region, which has said it will never renounce the use of force to bring Taiwan under China's control.

When asked if he thinks Chinese President Xi Jinping has a timetable to invade Taiwan, foreign minister Lin called the chatter of a time frame "a cognitive operation".

"We hope that when Xi Jinping wakes up every day, even if he has a timetable in mind, he will say, not today," Lin said. "We should not be constrained by his manipulation, but we have to show him our determination and capability."