Parliament has already approved the measure. But, under Switzerland's cherished direct democracy, the voters will have the last word in the referendum prompted by a challenge from conservatives.
The program, which has been operative since the early 1990s, allows the state to give daily doses of heroin to people who had previously scored their hits on the streets.
Supporters of the plan, which allows heroin use under medical supervision and accompanied by therapy, say it allows addicts to reintegrate into society, stay off the streets and hold a job. They say it also helps reduce crime, as addicts no longer need to rob or steal to get money for their next dose.
From a public health point of view, the program reduces the spread of infections, like HIV, as the addicts get to take their drugs using clean needles supplied to them in a safe environment. It also minimizes fatal overdoses.
Switzerland has 23 discreet centers which offer a range of support to nearly 1,300 addicts who haven't been helped by other therapies. Under careful supervision, they inject doses carefully measured to satisfy their cravings but not enough to cause a big high.
The aim is to help the addicts learn how to function in society, with counseling from psychiatrists and social workers.
Dr. Daniele Zullino, who heads the branch in Geneva, said that after two to three years in the program, one-third of the patients start abstinence-programs and one-third change to methadone treatment.
Besides, patients reduce consumption of other narcotics once they start the heroin program and suffer less from psychiatric disorders, he says.
Some other European governments have been looking at the Swiss to see how the program fairs. Polls show that a majority of the Swiss voters -- over 60 percent -- support keeping the program open past its current expiration date next year.
Over 1,000 patients are said to participate in the existing program, which is part of the Swiss government's drug policy that rejects an all-out war on drugs.
But opponents of relaxing the drug laws, particularly those from conservative groups, have said liberalization would turn the peaceful country into a "Mecca for drugs."
They reject the idea of government-sanctioned narcotics distribution, particularly without a plan to actually get addicts off the hard drug. They say that the government should get people clean, instead of tolerating and essentially supporting their habit.
The heroin program, Thomas Zeltur from the public health office told local radio a few weeks ago, only gives the drug to the worst addicts, such as those who failed at rehabilitation and have been abusing the substance for over a decade.
However, another drug issue up for referendum, the decriminalization of cannabis, is running tighter in the polls. Analysts don't expect it to pass, saying the Swiss are worried about the impact of such legislation on minors.
The debate has been ongoing in the confederation for years. Nonetheless, Switzerland is not known for being tough on pot. Personal possession of small amounts is generally tolerated among adults, DPA reported.