Temperature checks, queues for tests and inspections at airports -- Chinese authorities have stepped up health checks to snuff out the threat of a coronavirus resurgence.

China, where the virus first emerged around a year ago, largely contained its outbreak, and its economy has roared back to life.

But Beijing is taking few risks with coronavirus cases skyrocketing in many parts of the world and the threat of a new variant experts believe could be more transmissible.

Strict checks have been imposed across neighbourhoods in the capital Beijing, where suspected virus cases have been detected.

Workers in full PPE are spraying boats and airport arrival areas as part of a swift mobilisation to contain potential winter outbreaks.

Orderly queues snaked outside a testing site in the Shunyi district of Beijing, while officials checked health data stored on QR codes of visitors to Beijing hospitals.

China reported just 21 new cases on Monday, the majority imported.

The official national death toll remains at 4,634 with nearly 87,000 infections reported by authorities.