China imposed a strict lockdown on nearly half a million people in a province surrounding the capital to contain a fresh coronavirus cluster on Sunday, as authorities warned the outbreak was still "severe and complicated."

After China largely brought the virus under control, hundreds have been infected in Beijing and cases have emerged in neighbouring Hebei province in recent weeks.

Health officials said Sunday that Anxin county -- about 150 kilometres (90 miles) from Beijing -- will be "fully enclosed and controlled", the same strict measures imposed at the height of the pandemic in the city of Wuhan earlier this year.

Only one person from each family will be allowed to go out once a day to purchase necessities such as food and medicine, the county's epidemic prevention task force said in a statement.

The move comes after another 14 cases of the virus were reported in the past 24 hours in Beijing, taking the total to 311 since mid-June and spurring the testing of millions of residents.

The outbreak was first detected in Beijing's sprawling Xinfadi wholesale food market, which supplies much of the city's fresh produce, sparking concerns over the safety of the food supply chain.

Nearly a third of the cases so far have been linked to one beef and mutton section in the market, where workers are being made to quarantine for a month, city officials said Sunday.

Businesses in Anxin county had supplied freshwater fish to the Xinfadi market, state news agency Xinhua reported.

A new virus cluster has prompted fears of a resurgence of COVID-19 in China
A new virus cluster has prompted fears of a resurgence of COVID-19 in China AFP / GREG BAKER

Some 12 cases of the novel coronavirus were found in the county -- including 11 linked to Xinfadi, the state-run Global Times reported.

The new cases in Beijing have prompted fears of a resurgence of the virus in China.

The capital has mass-tested wholesale market workers, restaurant workers, residents of medium and high-risk neighbourhoods and delivery couriers over the past two weeks.

At a press conference on Sunday, officials said 8.3 million samples have been collected so far, of which 7.7 million have already been tested.

Testing has now expanded to include all employees of the city's beauty parlours and hair salons, the Global Times said.

Beijing city official Xu Hejian told reporters Sunday that "the epidemic situation in the capital is severe and complicated," warning that the city needed to continue tracing the spread of the virus.

City officials have urged people not to leave Beijing, closed schools again and locked down dozens of residential compounds to stamp out the virus.

But Wu Zunyou, chief epidemiology expert at the Chinese Center for Disease Control and Prevention, told reporters last week the new outbreak had been "brought under control", and officials lifted a weeks-long lockdown imposed on seven Beijing communities on Friday.