BEIJING/TAIPEI China on Monday extended an investigation into what it calls Taiwan's trade barriers against it by three months to the eve of the island's presidential election, prompting Taipei to accuse Beijing of attempting to interfere in the vote.

Taiwan, which China claims as its own territory, frequently accuses Beijing of seeking to exert pressure, whether military or economic, to sway the outcome of its elections to ensure an outcome favourable to the Chinese government.

China's Commerce Ministry originally announced the probe into what it says are Taiwan's trade barriers in April, but has now extended the investigation period to Jan 12, one day before Taiwan's presidential and parliamentary elections.

The Taiwanese government's Office of Trade Negotiations said the extension of the probe "once again proves that China's so-called trade investigation is politically motivated and an attempt to interfere with our elections with economic coercion".

Extending the date to Jan 12, just before the election, "highlights the political motivations" behind the decision, it added.

It also violated the norms of the World Trade Organization, the office said, of which both Taiwan and China are members.

"We have said many times that any bilateral trade issues should be resolved through consultation between the two sides in accordance with WTO mechanisms. We also once again call on China to return to the right track and not to repeatedly manipulate trade issues politically."

The brief statement from China's Commerce Ministry into the extension gave no details or explanation for why they made the decision.

Taiwan has denounced what it calls Chinese economic coercion before, including China's punishment of Lithuania with trade measures after the European Union member allowed Taipei to open a de facto embassy in Vilnius.

China's government has refused to speak to the government of Taiwan President Tsai Ing-wen, who it accuses of being a separatist. She has repeatedly offered talks with China, but says only Taiwan's people can decide their future.

Tsai's deputy, Vice President William Lai, is the frontrunner to be Taiwan's next president, according to opinion polls. He has also offered to talk to China, thought it also calls him a separatist.

  - Reuters