Workers partially demolished a Chinese hospital with several doctors and a patient still inside, media reported Saturday, burying bodies stored in its morgue under rubble and prompting an investigation.

Around 20 people dressed in military fatigues on Thursday destroyed part of Fourth Affiliated Hospital of Zhengzhou University, Huiji district, in the capital of central Henan province, according to the public television channel CCTV.

"I was operating...(an X-ray) machine. The noise (of the demolition) was terrifying," Liu Chunguang, the hospital's director of radiology, told the channel.

"My patient was sitting beside me, shouting that there was an earthquake. The patient ran away, terrified," he said, adding that only a few doctors and one patient were in the hospital at the time.

Images published by Chinese media apparently taken at the site show several rooms with collapsing ceilings, holes through brick walls, swinging lights as well as masses of loose cables and debris.

The hospital's morgue was "razed", according to local newspaper Dahebao, and six of the bodies stored there covered in rubble, while medical equipment worth 4 million yuan ($600,000) was damaged.

Three hospital employees were injured during a confrontation with the demolition workers, CCTV reported.

Authorities in Huiji district told AFP Saturday that they were currently investigating the incident but results would not be announced before Monday.

On Friday they said they had not yet identified the people who carried out the demolition. The buried bodies had also yet to be recovered.

"It must be the business which is carrying out roadworks (near the hospital) which ordered this!" one person said in an online forum. Forced demolitions are frequent in China.

Other internet users criticised local media for not sufficiently covering the demolition, which only received widespread attention when it was picked up by CCTV.