With China days away from dropping border controls that have effectively shut it off from the rest of the world for three years, countries are lining up to impose curbs on travelers from China to contain its raging COVID-19 outbreak.

From Sunday, Jan. 8, China will drop a requirement for inbound travelers to quarantine, the latest dismantling of its "zero-COVID" regime that began last month following historic protests against a suffocating series of mass lockdowns.

But the abrupt changes have exposed many of China's 1.4 billion population to the virus for the first time, triggering an infection wave that is overwhelming some hospitals, emptying pharmacy shelves of medication and causing international alarm.

Greece, Germany and Sweden on Thursday joined more than a dozen countries to demand COVID tests from Chinese travelers, as the World Health Organisation said China's official virus data was under-reporting the true extent of its outbreak.

Chinese officials and state media have struck a defiant tone, defending the handling of the outbreak, playing down the severity of the surge and denouncing foreign travel requirements on its residents.

"No matter how China decides to deal with the COVID-19 epidemic, some Western media and some Western politicians will never be satisfied," the state-run Global Times wrote in an editorial late on Thursday.