"Hong Kong police confirmed to local press that two male dancers were hospitalised.
A local hospital said one performer suffered neck injuries and was in serious condition in intensive care while another was stable, the South China Morning Post reported. Those injured have not been named.
Several female concert goers were also treated for shock.
The boy band had been performing at the Hong Kong Coliseum on Thursday night as part of a series of shows.
The city's government has ordered the remainder of the tour to be put on hold until safety checks are carried out at the other venues.
"I am shocked by the incident" said the city's new leader John Lee, adding "I express sympathy to those who were injured and hope that they would recover soon".
Hong Kong's Chief Executive also ordered city agencies to "comprehensively investigate the incident".
The group is wildly popular in the city and are often credited with revitalising Cantopop - local Hong Kong pop music.
Its members are some of the most recognisable celebrities in Hong Kong today.
The band was formed in 2018 and have since experienced break out success in recent years reaching audiences across Asia."
