"Fix rooms" for drug addicts would bring so many benefits it would be ridiculous not to have them in the UK, a homeless charity has said.
Lindsay Cordery-Bruce, chief executive of Welsh charity The Wallich, said supervising substance use at medical-grade facilities would cut drug deaths.
She said the biggest challenge was legislation and policy.
But a woman whose daughter was addicted to heroin said such facilities could entice addicts to continue using.
Drug consumption rooms allow users to take illegal substances under supervision in a clinical setting.
But a range of offences could be committed in running such a facility, such as possession of a controlled drug and encouraging or assisting the possession and supply of controlled drugs.
The Home Office said there was "no legal framework for the provision of drug consumption rooms in the UK" and it had "no plans to introduce them".
North Wales Police and Crime Commissioner Arfon Jones supports the idea of fix rooms and wants to hold a pilot project to look into the idea.
Glasgow City Council proposed a "fix room" but on Monday the Home Office drugs legislation team said it could not support its creation.
Ms Cordery-Bruce said: "There's a whole landslide of evidence from across Europe showing that these are an effective tool for engaging people, for getting people off the streets, for making sure people have got appropriate injecting technique, that works are disposed of safely.
"There's just so many benefits it would be ridiculous not to have them in the UK."
Caroline Phipps, chief executive of harm reduction drug and alcohol service Barod, has visited consumption rooms in Barcelona and north America
She said: "They work brilliantly in those areas. There's a duty to explore different ways of keeping people safe from harm but we're at the mercy of the law led by Westminster.
"It is important to have evidence and we should look into the feasibility in Wales."
But a woman from Cardiff whose daughter was addicted to heroin does not believe this is the answer.
The woman, in her 60s, who the BBC is not naming to protect her daughter's identity, cared for her grandchild for six years while her daughter struggled with addiction and was in an abusive relationship.
She eventually beat her addiction using heroin substitute methadone but her mother does not believe "fix rooms" would have helped.
"You're opening rooms for them to use but they're killing themselves and they're not doing anything about it," she said.
"Open rooms to talk to them and get them off the drugs. I know people inject in parks and different things but these rooms would entice them more so."
The Home Office said the UK's approach was to "prevent drug use in our communities and support people dependent on drugs through treatment and recovery".
A Welsh Government spokeswoman said: "The law in this area is a matter for the UK government and its enforcement is a matter for the police.
"Also, a recent report by our independent Advisory Panel on Substance Misuse could not, based on the available evidence, recommend that enhanced harm reduction centres are implemented in Wales."