BEIJING (AFP, REUTERS) - Nearly 30 million people were under lockdown across China on Tuesday (March 15), as surging virus cases returned mass tests and hazmat-suited health officials to city streets on a scale not seen since the start of the pandemic.

China reported 5,280 new Covid-19 cases on Tuesday, more than double the previous day's tally as the highly transmissible Omicron variant spreads across the country.  

Tuesday was the sixth day in a row that China reported more than 1,000 new virus cases.

China has tethered tightly to a "zero-Covid-19" strategy, which pivots on hard localised lockdowns. That approach has left the country virtually cut off from the outside world for two years, and is now on the line as Omicron finds its way into communities.

At least 13 cities nationwide were fully locked down on Tuesday, while various other cities had partial lockdowns.

The worst-hit area is the north-eastern province of Jilin, which accounted for more than 3,000 new cases on Tuesday, according to the National Health Commission.

Residents of several cities there including the provincial capital of Changchun – home to nine million people – are under stay-at-home orders.

An outbreak at Volkswagen Group factories in Changchun also prompted three sites to shut on Monday for at least three days, according to a spokesman.

Shenzhen – the southern tech hub of 17.5 million people – is three days into a lockdown, with many factories closed and supermarket shelves emptying.

China’s largest city Shanghai is under a lattice of restrictions, with certain neighbourhoods and buildings sealed off. 

China’s aviation regulator announced earlier on Tuesday that it will divert 106 international flights scheduled to arrive in Shanghai to other domestic cities from March 21 to May 1 due to the Covid-19 situation.

The impacted flights include those operated by Air China, China Eastern, Shanghai Airlines, Juneyao Air and Spring Airlines, the Civil Aviation Administration of China said.

Scenes of closed neighbourhoods, panic buying and police cordons have cast back to the early phase of the pandemic, which was first detected in China in late 2019 but has eased in much of the rest of the world.

A Covid-19 forecasting system run by Lanzhou University in China’s north-west predicted that the current round of infections would eventually be brought under control in early April after an accumulated total of around 35,000 cases.

The university said in its latest assessment published on Monday that while the current outbreak was the most serious on the mainland since it was first detected in Wuhan in 2020, China could bring it under control as long as stringent curbs remained in place.

But experts have forecast a dent to growth as the virus billows out.

“The recent Covid-19 outbreak and renewed restrictions, notably the lockdown in Shenzhen, will weigh on consumption and cause supply disruptions in the near term,” Dr Tommy Wu of Oxford Economics said in a briefing note.

He added that it will be “challenging” for China to meet its official gross domestic product growth target for the year of around 5.5 per cent.

Hong Kong stocks plunged by more than 3 per cent on Tuesday, extending the previous day’s tech-fuelled rout.

A top Chinese medical expert, Dr Zhang Wenhong, has raised the prospect of softening the zero-Covid-19 strategy in the face of Omicron. But in the short term, he warned that any relaxation of mass testing and lockdowns was impossible.

Health officials also say tighter restrictions could be on the way.

The governor of Jilin vowed to go all out to "achieve community zero-Covid-19 in a week" during an emergency meeting on Monday night, state media reported.

As at March 14, mainland China had reported 120,504 cases with confirmed symptoms, including both local ones and those arriving from outside the mainland.

There were no new deaths, leaving the death toll unchanged at 4,636.