WHO warns China of COVID holiday outbreak

People in China are worried about spreading COVID-19 to aged relatives as they plan to return to their home towns for holidays the World Health Organisation warns could inflame a raging outbreak.

The Lunar New Year holiday, which officially starts on January 21, comes after China last month abandoned a strict anti-virus regime of mass lockdowns that prompted widespread frustration and boiled over into historic protests.

That abrupt U-turn unleashed COVID on a population of 1.4 billion which lacks natural immunity, having been shielded from the virus since it first erupted in late 2019, and includes many elderly who are not fully vaccinated.

The outbreak spreading from China's mega-cities to rural areas with weaker medical resources is overwhelming some hospitals and crematoriums.

With scant official data from China, the WHO on Wednesday said it would be challenging to manage the virus over a holiday period considered the world's largest annual migration of people.

Other warnings from top Chinese health experts for people to avoid aged relatives during the holidays shot to the most-read item on China's Twitter-like Weibo on Thursday.

More than two billion trips are expected across China during the broader Lunar New Year period, which started on Saturday and continues for 40 days, according to the transport ministry.

That is double last year's trips and 70 per cent of those seen in 2019 before the pandemic emerged in the central Chinese city of Wuhan.

The WHO and foreign governments have criticised China for not being forthright about the scale and severity of its outbreak, which has led several countries to impose restrictions on Chinese travellers.

China has been reporting five or fewer deaths a day in the past month, numbers that are inconsistent with the long queues seen at funeral homes.

The country did not report COVID death data on Tuesday and Wednesday.

Liang Wannian, the head of a COVID expert panel under the national health authority, told reporters deaths could only be accurately counted after the pandemic was over.

Although international health experts have predicted at least one million COVID-related deaths this year, China has reported just over 5000 since the pandemic began, a fraction of what other countries have reported as they removed restrictions.

Looking beyond the death toll, investors are betting China's reopening will reinvigorate a $US17 ($A25) trillion economy suffering its lowest growth in nearly half a century.

After three years of isolation from the outside world, China on Sunday dropped quarantine mandates for inbound visitors in a move expected to eventually also stimulate outbound travel.

But concerns about China's outbreak have prompted more than a dozen countries to demand negative COVID test results from people arriving from China.

South Korea and Japan have also limited flights and require tests on arrival, with passengers showing up as positive being sent to quarantine.

In a deepening spat between the regional rivals, China has in turn stopped issuing short-term visas and suspended transit visa exemptions for South Korean and Japanese nationals.

Despite Beijing's lifting of travel curbs, outbound flight bookings from China were at only 15 per cent of pre-pandemic levels in the week after the country announced it would reopen its borders, travel data firm ForwardKeys said on Thursday.