Taipei has accused Beijing of conducting its biggest maritime drills in years.

Dozens of Chinese ships have simulated attacking foreign vessels and disrupting sea routes around the self-ruled island, according to security officials in Taiwan.

Plans for the massive exercises began in October and were aimed at showing that China could choke off Taiwan and to "draw a red line" ahead of the next Donald Trump administration, a senior national security official told AFP.

There has been no public announcement by Beijing's army or Chinese state media about increased military activity in the East China Sea, Taiwan Strait, South China Sea or Western Pacific Ocean.

"Harming the peace and stability of the Taiwan Strait is the work of Taiwan independence separatist forces, with the support of external actors," foreign ministry spokeswoman Mao Ning said at a regular news conference in Beijing.

When asked about the drills drawing a "red line" before Trump's return, Mao said: "The Taiwan issue is the first red line that cannot be crossed in China-US relations, this is our consistent position."