Data from China shows no new COVID-19 variant has been found there but the country under-represents how many people have died in a rapidly spreading outbreak, World Health Organization (WHO) officials say.

Global unease has grown about the accuracy of China's reporting of an outbreak that has filled hospitals and overwhelmed some funeral homes since Beijing abruptly reversed its "zero COVID" policy.

The United Nations agency was releasing data provided by the Chinese Center For Disease Control and Prevention (CDC), a day after WHO officials met Chinese scientists.

China has been reporting daily COVID deaths in single figures.

Mike Ryan, the WHO's emergencies director, told a media briefing that current numbers being published from China under-represent hospital admissions, intensive care unit patients and "particularly in terms of death".

WHO Director-General Tedros Adhanom Ghebreyesus said the UN agency was seeking more rapid and regular data from China on hospitalisations and deaths.

"WHO is concerned about the risk to life in China and has reiterated the importance of vaccination, including booster doses to protect against hospitalisation, severe disease and death," he said.

China's People's Daily, the Communist Party's official newspaper, sought to rally worried citizens for what it called a "final victory" over COVID-19, rebutting criticism of its policy of strict isolation that triggered rare protests last year.

Beijing's abrupt axing of those ultra-strict curbs last month has unleashed the virus on the nation's 1.4 billion people, who have little immunity after being shielded since it emerged in the Chinese city of Wuhan three years ago.

Health officials abroad have been struggling to work out the scale of the outbreak and how to stop it from spreading, with more countries introducing measures such as pre-departure COVID tests for arrivals from China - moves Beijing has criticised.

European Union officials recommended on Wednesday that passengers flying from China to the EU should have a negative COVID-19 test before they board.

The EU's Integrated Political Crisis Response group, a body made up of officials from the 27 represented governments, also called for testing and sequencing of wastewater on planes arriving from China and at airports that handle international flights, among other measures.

China's CDC analysis showed a predominance of Omicron sublineages BA.5.2 and BF.7 among locally acquired infections, according to the data reported by the WHO.

Omicron remains the dominant coronavirus variant based on recent genomic sequencing, confirming what scientists had already said but allaying concerns for now about a new variant of concern emerging.

Many Chinese funeral homes and hospitals say they are overwhelmed, and international health experts predict at least one million COVID-related deaths in China this year.

China has reported five or fewer deaths a day since the policy U-turn.

"That is totally ridiculous," 66-year-old Zhang, a Beijing resident who only gave his last name, said of the official toll.

"Four of my close relatives died. That's only from one family. I hope the government will be honest with the people and the rest of the world about what's really happened here."

China's cabinet said on Wednesday it would step up medicine distribution and meet demand from medical institutions, nursing homes and rural areas, state media reported.

Beijing has hit back against some countries demanding visitors from China show pre-departure COVID tests, saying the rules are unreasonable and lack a scientific basis.

Japan, the United States, Australia and several European states are among countries requiring such tests.

China will stop requiring inbound travellers to quarantine from Sunday but they must be tested before arrival.

China reported five new COVID deaths for Tuesday, bringing the official death toll to 5258 - very low by global standards.

British-based health data firm Airfinity has estimated about 9000 people in China are probably dying each day from COVID.