A senior medic has called for a major theatre to be temporarily shut after claiming they failed to enforce Covid mask rules.
The consultant, who does not wish to be named, said he left a show at the Wales Millennium Centre, after about 80% of audience took off their masks.
The medic, who has had his tickets refunded, said people were "coughing all over the place".
The WMC said safety at the venue was of "paramount importance".
The consultant said he had seen people die with Covid and felt he had to leave the performance of the musical Grease last Thursday, due to a lack of compliance with rules.
"The theatre was well attended; in my area the rows were fully taken," he told BBC Wales.
"Coughing and spluttering was to be heard and seen all over the place."
He claimed that neither staff nor on-site security enforced the rules, which he said were "disturbing failures".
"There was mere reference to the relevant announcements and otherwise helpless shoulder-shrugging," he added.
Since the 15 November, Covid passes have been needed to enter cinemas, theatres, concert halls along with nightclubs and large events.
Face coverings are required for anyone aged 11 and above unless they are medically exempt, and are meant to be worn in all indoor places, including in shops and cinemas.
They are not required to be worn in hospitality venues such as cafés, restaurants and pubs, where people eat and drink.
The Donald Gordon Theatre can seat almost 2,500 people.
"I've seen people die with Covid and I was was seriously ill with the virus," he said.
"The Heath hospital is full and we just cannot afford to have some sort of mass-spreading event."
He has has written to the Welsh government and also lodged a complaint with Cardiff Council.
Environmental health issues are managed and enforced by the Shared Regulatory Services (SRS) partnership which covers Cardiff, Bridgend and the Vale of Glamorgan.
BBC Wales was told SRS health officials had recently received other queries about the WMC and was aware of concerns raised.
Head of Operations at WMC, Steven Morris, said: "The safety of our audience, staff and performers is of paramount importance to us.
"We are working extensively to ensure the Centre is Covid-secure and the measures we carry out are in line with the latest government legislation and performing arts guidelines."