According to the Norwegian Institute for Alcohol and Drug Research (SIRUS), heroin overdoses accounted for 30% of 262 fatal overdoses in 2011. By comparison, only 168 people died in traffic accidents that year.

The city of Oslo has opened a supervised injection site in a bid to reduce overdoses, but decriminalizing heroin smoking would also help, said Stoere. Users currently can't smoke at the supervised injection site.

"This isn't about some kind of legalization of heroin but about being realistic," he said."Those who are in the unfortunate situation of injecting themselves in a drug room should be able to inhale. It is less dangerous, you consume less and the risk of contracting a disease is lower," he added.

"It's a paradox that you can't smoke heroin when you can inject it, since the first method is less dangerous than the second," SIRUS researcher Astrid Skretting told AFP. "But the culture of injecting which provides a more immediate effect than smoking seems deeply rooted in Norway and it's not certain that a decriminalization will lead to a radical change in behavior," she suggested.

The Norwegian government is set to unveil its latest plan for fighting drug addiction next week. Stoere said the heroin smoking decrim plan has the backing of the center-left government.