China has recorded the biggest daily jump in COVID-19 cases in more than five months, despite four cities in lockdown, increased testing and other measures aimed at preventing another wave of infections in the world's second biggest economy.

Most of the new patients were reported near Beijing, but a province in northeast China also saw a rise in new cases, official data showed on Wednesday, amid a resurgence that has seen more than 28 million people under home quarantine.

The National Health Commission said in a statement that a total of 115 new confirmed cases were reported in the mainland compared with 55 a day earlier. This was the highest daily increase since July 30.