The number of seriously ill COVID patients is reportedly surging in Beijing and other parts of China, straining the country's medical system.

Coronavirus infections have been spreading rapidly in many regions since the Chinese government eased its strict pandemic restrictions on December 7.

Chinese media say one university hospital in the capital is treating more than 500 patients in serious condition a day.

The number of such patients is also increasing in China's inland provinces, where medical facilities and personnel are less equipped to deal with an outbreak.

At an emergency care department at a hospital in Anhui Province, the entire medical staff have reportedly tested positive. With no backup available, they are apparently staying on duty while taking fever medication.

The department is reportedly examining more than 1,000 people a day, prioritizing those at higher risk, such as the elderly and patients with underlying health conditions.

A photo released by Reuters on Wednesday shows a long line of vehicles waiting at a crematorium in Chengdu, Sichuan Province, suggesting the death toll is running high.

Official figures state there were just three COVID deaths nationwide on Tuesday. But an infectious disease expert in the country says the figure does not include people with underlying health conditions who died after being infected.