Beijing has criticised recently imposed testing requirements on passengers from China and threatened countermeasures against countries involved.
China is experiencing a nationwide outbreak of the coronavirus after abruptly easing restrictions that were in place for much of the pandemic.
Countries including the US, UK, India, Japan and several European nations have announced tougher measures on travellers from China amid concerns over a lack of data on infections and fears of the possibility that new variants may emerge.
“We believe that the entry restrictions adopted by some countries targeting China lack scientific basis, and some excessive practices are even more unacceptable,” foreign ministry spokesperson Mao Ning said at a briefing.
“We are firmly opposed to attempts to manipulate the Covid measures for political purposes and will take countermeasures based on the principle of reciprocity.”
The comments were China’s sharpest to date on the issue as Australia and Canada this week joined a growing list of countries requiring travellers from China to take a Covid test before boarding their flight.
The US was among several countries to defend the Covid tests.
“This is an approach that is based solely and exclusively on science,” US state department spokesperson Ned Price told reporters when asked about the statement by his Chinese counterpart.
The measures have “very public health concerns that undergird them” due to “the surge of Covid-19 cases in the PRC and the lack of adequate and transparent epidemiological and viral genomic sequence data being reported from the PRC,” Price said, referring to the People’s Republic of China.
Price reiterated that the US was ready to share its Covid vaccines with China, which has heavily promoted overseas its own jabs that international health experts say are less effective.
The French prime minister, Élisabeth Borne, also defended travel requirements. Starting from Wednesday, anyone flying from China to France will have to present a negative virus test taken within the previous 48 hours and be subject to random testing on arrival.
“We are in our role, my government is in its role, protecting the French,” she told France-Info radio.
Australia said it would not be swayed by China’s threat of retaliation, with treasurer Jim Chalmers telling national broadcaster ABC “countries will make their own decisions about travel arrangements and how they manage Covid more broadly”.
He said the requirement for a pre-flight Covid test was not “especially onerous” and “consistent with the steps being taken in other countries”.
Asked if the requirement had been internationally coordinated to pressure China, Chalmers said: “I don’t see it precisely like that but there certainly is a lot of concern around the global health community … about the transparency and quality of data that we see out of China on Covid.”
World Health Organization (WHO) officials met Chinese scientists on Tuesday amid concerns over the accuracy of China’s data on the spread and evolution of its outbreak.
The UN agency had invited the scientists to present detailed data on viral sequencing and to share data on hospitalisations, deaths and vaccinations.
A spokesperson said the agency expected a “detailed discussion” about circulating variants in China, and globally.
New Zealand bucked the wider trend, and said on Wednesday it would not require travellers from China to produce a negative Covid test.
China, which for most of the pandemic adopted a “zero-Covid” strategy that imposed harsh restrictions aimed at stamping out the virus, abruptly eased those measures in December.
Chinese authorities previously said that from 8 January, visitors would no longer need to quarantine upon arriving in China, paving the way for Chinese residents to travel.
Associated Press and Agence France-Presse contributed to this report