China has reported the highest daily count of Covid-19 cases arriving from outside the mainland in nearly two years, with infections mostly from Hong Kong as the financial hub grapples with a wave.

The mainland detected a total of 142 imported cases with confirmed symptoms, the National Health Commission (NHC) said.

It marks the highest imported caseload since the authority began classifying domestically transmitted cases and infected travellers from outside the mainland separately, in March 2020, according to Reuters.

More than 100 imported cases came from Hong Kong, with 47 reported in the southern city of Shenzhen and 51 in the eastern municipality of Shanghai, local health authorities' bulletins showed.