Hong Kong police have launched an investigation after a man was caught on camera spitting on residents’ doors in a block of flats.

The five-second clip, apparently taken by a security camera, was posted on Sunday evening on a Kwai Chung community Facebook page and shows a man in his 30s dressed in black jeans and hooded top walking along the corridor of a housing block.

The man, who has what appears to be a bottle of tea in his hand, pulls down his black surgical mask and spits on the metal gates and doorbells of two flats before disappearing out of view.

Health workers at the coronavirus-hit Kwai Chung Estate.

A message from the Facebook user who posted the video urged group members in Kwai Chung Estate – the site of a growing coronavirus outbreak – to keep an eye out for the spitter, saying similar incidents had occurred at three blocks there, although no proof was provided.

More than 170 Covid-19 infections have been reported on the huge 16-block estate, with two buildings currently under five-day lockdowns for Covid-19 testing of residents in a bid to curb the escalating outbreak.

A top government pandemic adviser warned on Sunday that cases would continue to be uncovered over the next two weeks after scores of residents were found to be infected with the highly transmissive Omicron variant.

The Facebook user provided no details on where and when the footage was taken, but a time stamp on the clip records it as around 6.46pm on Saturday.

Lawmaker Ben Chan Han-pan said he had contacted police about the incident.

He slammed the spitter, accusing him of acting badly when all Hongkongers were fighting hard against the pandemic including estate residents who were under lockdown.

“I’ve already suggested to the police district commander to hunt for him. If such people are let go, others may follow suit,” Chan said.

A police source said investigators had yet to find out basic details about the clip. Officers were trying to identify the man and collect intelligence from frontline security guards on the estate.

They were also contacting the Facebook account holder to ask for the source of the video.

A police spokesman, who said no arrests had been made, called for anyone with information to come forward.

The Post has contacted the Facebook group for further information.