On the face of it, giving drug addicts free heroin is a contentious move, but that is exactly what happens in Switzerland.

A referendum last year was overwhelmingly passed to approve the program, which has been running for years as a trial.

It gives security to a system designed for those addicts who have failed all other treatment options. But it is not without its critics.

On an early morning in the heroin clinic, addicts line up for their turn to receive a syringe with a carefully measured dose of pure heroin.

They take it to a desk and either self-inject, or get a staff member to help.

Amongst the regulars is Jason. He still hopes to kick the habit, but says until then it is a whole lot better than his old life on the streets.

"Before I was on the program I was totally down to the floor. I was around not even 60 kilos," he said.

"I lost my job, I lost my apartment; I looked like shit.

"And then when I came here I was able to work again, I gained quite a lot of weight since then also and then I can be back to life.

"[If I didn't have this program] I would probably be dead."

Dr Christoph Buerki runs the Berne clinic. He has around 200 clients and says the program is good for addicts and for society.

"Once a patient enters our treatment he would very much to a large degree - and the statistics have proven that - would reduce his illegal activities," he said.

"So that's one very, very important point also for society."

Dr Buerki denies criticism that the program is just feeding the addiction and not actually controlling it.

"They come here from the heroin, but once you have them in treatment, you start working with them," he said.

"There's a whole lot of treatment involved in it."

Despite the referendum approving of this program by a two-thirds majority, it is not without its critics, like Sabine Geissbuhler from Parents Against Drugs.

She argues the system just feeds a habit rather than looking for a cure.

"I think it's very bad because there is no goal to make them free of drugs because you can't get free from a drug if you give it," she said.

Whatever side of the argument you are on, no-one would want a return to the early 90s, where public parks in the major cities were turned into drugs bazaars.

Evelyn is a long-term user who is still on the program. She returns to the Berne park where she used to buy her drugs.

It looks very different and a metre of topsoil has to be removed because used needles had contaminated the soil.

The ABC's Foreign Correspondent first met Evelyn 12 years ago when she had joined the heroin trial to escape a life of degradation.

"[I was] begging in the streets for instance or even prostitution. I didn't do that very much, but [I did it and] I hate myself for this," she told the program.

But she says these days life is better.

"I'm still on heroin, but I don't drink anymore, I don't run after the drugs, I don't have to lie to anybody anymore," she said.

Detractors say the fact she is still an addict after all these years is evidence the program has failed.

But she says the fact she is alive and living a productive life without resorting to crime is clear evidence of its success.

Either way, conservative Switzerland opted for a radical solution, one some say could work equally well in places like Australia.