Military tensions between the island and China, which claims Taiwan as its own territory, are at their worst in more than 40 years, Taiwan's defence minister said last week.

Chiu Kuo-cheng added China will be capable of mounting a "full scale" invasion by 2025.

He was speaking after China mounted four straight days of mass air force incursions into Taiwan's air defence identification zone that began on October 1, part of a pattern of what Taipei views as stepped up military harassment by Beijing.

Speaking at a regular news briefing in Beijing, Ma Xiaoguang, spokesman for China's Taiwan Affairs Office, said the cause of current tensions was Taiwan's ruling Democratic Progressive Party's (DPP) "collusion" with foreign forces and "provocations" over seeking Taiwan's independence.

Chinese drills are aimed at this collusion - a veiled reference to US support for Taiwan - and separatist activities, protecting the country's sovereignty and territorial integrity as well as peace and stability in the Taiwan Strait, he said.

"The DPP authorities' hyping of the so-called 'military threat' of the mainland is to completely invert right and wrong, and a bogus accusation," Ma said.

"If the DPP authorities obstinately persist in going about things the wrong way, and do not know how to draw back from the edge, it will only push Taiwan into a more dangerous situation."

Taiwan says it is an independent country called the Republic of China, its formal name, and will defend its freedom and democracy.

Despite Ma's comments, China's President Xi Jinping and Taiwan's leader Tsai Ing-wen made relatively conciliatory speeches at the weekend, even as Xi vowed to bring Taiwan under control, and Tsai said they would not be forced to bow to China.

Xi did not mention resorting to force over Taiwan, while Tsai reiterated a desire for peace and dialogue with China.

Australian Associated Press