The Consumer Council on Wednesday said the operators of bouldering gyms shouldn't expect that getting people to sign a waiver will let them off the hook if a customer injures themselves or even dies.

The council said it looked into 10 indoor bouldering gyms from October to December last year and found that nine claimed they would be free of any responsibility if an accident was caused by a customer's "negligence".

However, the chief executive of the council, Gilly Wong, said even if customers have signed a waiver, bouldering gyms still have legal responsibility.

"We want to remind gym operators that they should not have a concept that by having a disclaimer, their responsibility could be completely waived," she said.

"Under the Control of Exemption Clauses Ordinance, operators cannot rely on a disclaimer to limit their liability for the injury or death of a consumer due to negligence. This won't affect consumers' right to seek compensation."

The watchdog said one of the gyms it examined did not tell customers that the back page of a personal information form was a waiver. A waiver may lose its validity if customers are unaware of its existence, the council warned.

It added that gym operators should take the initiative to explain the content of waivers to customers, while people should make sure they understand the details of such documents before signing.