New Zealand's foreign minister on Tuesday said the country has to stand up for itself after China warned its backing of Taiwan's participation at the World Health Organization (WHO) could damage bilateral ties.

Taiwan, with the strong support of the United States, has stepped up its lobbying to be allowed to take part as an observer at next week's World Health Assembly (WHA), the WHO's decision-making body - a move which has angered China.

Taiwan is excluded from the WHO due to the objections of China, which views the island as one of its provinces.

Senior ministers in New Zealand last week said Taiwan should be allowed to join the WHO as an observer given its success in limiting the spread of the novel coronavirus, drawing China's ire which asked the Pacific country to "stop making wrong statements".

"We have got to stand up for ourselves," Winston Peters, New Zealand's foreign minister, said at a news conference when asked about China's response to New Zealand's position on Taiwan.

"And true friendship is based on equality. It's based on the ability in this friendship to nevertheless disagree."

Peters said he did not think the issue would harm diplomatic ties with China, which is New Zealand's biggest trading partner.

Taiwan has reported only 440 coronavirus cases and seven related deaths, relatively low figures attributed to early and effective disease prevention and control work.

Peters praised Taiwan's response to COVID-19, the disease caused by the novel coronavirus, and said there was a lot for other countries to learn from.

"New Zealand's position on Taiwan is about its tremendous success against COVID-19," Peters said.

When asked about China's response later in the day, Prime Minister Jacinda Ardern said New Zealand's position on Taiwan was only related to its health response to COVID-19.

"We have always taken a 'One China' policy, and that continues to be the case," Ardern said.

Speaking in Taipei, Taiwan Foreign Ministry spokeswoman Joanne Ou expressed thanks for New Zealand's support, saying both countries were staunch supporters of freedom, democracy and human rights and that Taiwan would deepen ties with New Zealand.

Taiwan expresses regret at China's threats against New Zealand, Ou said, adding the response from China's foreign ministry was "hysterical".

Ties between neighbouring Australia and China have frayed in recent months after Canberra called for an international investigation into the origins and spread of the coronavirus that was first reported in the Chinese city of Wuhan late last year.

China has dismissed such a probe as groundless, saying the country has been open and transparent about the outbreak.