A performing arts union has said new temporary measures to improve stage safety are reasonable but may not be enough.

The government on Monday brought in a series of short-term rules for organisers on stage design and the use of mechanical equipment as it investigates an incident in which a giant video screen fell onto the stage at last Thursday's MIRROR gig, injuring two dancers, one of them seriously.

Sonic Lee from the Hong Kong Theatre Arts Practitioners Union said it wasn't yet known whether the accident involved human error or a technical fault, and that it was therefore too early to say if the beefed up measures would be enough.

Speaking to RTHK's Hong Kong Today, he added: "The union hopes the results of the government's investigation will be available as soon as possible, as it's affecting the industry and whether we can work safely. We hope the content of the investigation can be open and clear for everyone."

Lee also welcomed the setting up of a task force for the sector as this would allow practitioners to carry on dialogue with the government.