Health authorities on Saturday reported a Covid-19 outbreak at a club in Central, where 11 patrons have come down with the virus.

Officials reported 270 new infections for the day, including 31 that were imported.

The Centre for Health Protection said the Covid infections centred on Zentral, located at California Tower in Lan Kwai Fong.

Authorities said the 11 customers, six men and five women aged between 17 and 29, visited the bar from 11pm onwards on May 21.

Bars in Hong Kong were allowed to reopen on May 19 and stay open until 2am.

Albert Au from the centre said authorities were investigating how many customers were at the venue at the time and whether any rules were broken.

He noted that records from the LeaveHomeSafe app showed that the last of the customers left at 5am. But he said some people could have forgotten to press the leave button on the app.

"Many of the cases told us they went on their own or with one or two friends. They told us they walked around to drink and chat with others without wearing a mask," Au said. "Our initial understanding is that the 11 people didn't know each other."

He said one of the 11 customers, a 23-year-old man, is a part-time basketball coach at POH Tang Pui King Memorial College in Yuen Long and six players he coached have since tested positive for the virus.

The players didn't wear masks during the training session, but the coach did, Au added. The other 24 people in the group are being asked to quarantine at home.

Meanwhile, authorities said one more students at the DSC International School in Taikoo Shing had tested positive to Covid, taking the number of people infected in the cluster to five.

Officials said further investigations have revealed one of the infected primary school student lives in the same Taikoo Shing block as an earlier patient from a cluster linked to a nearby McDonald's restaurant.

They said the primary school pupil lives on a floor above the Covid patient, but further investigations are needed to see whether the two cases are linked.

The Hospital Authority reported the death of one further Covid patient.