Major international divisions over the global "war on drugs" have been revealed in a leaked draft of a UN document setting out the organisation's long-term strategy for combating illicit narcotics.

The draft, written in September and seen by the Observer, shows there are serious and entrenched divisions over the longstanding US-led policy promoting prohibition as an exclusive solution to the problem.

Instead, a number of countries are pushing for the "war on drugs" to be seen in a different light, which places greater emphasis on treating drug consumption as a public health problem, rather than a criminal justice matter.

It is rare for such a document to leak. Normally only the final agreed version is published once all differences between UN member states have been removed.

The divisions highlighted in the draft are potentially important. The document will form the basis of a joint "high-level" statement on drugs to be published in the spring, setting out the UN's thinking. This will then pave the way for a general assembly review, an event that occurs every 10 years, and, in 2016, will confirm the UN's position for the next decade. "The idea that there is a global consensus on drugs policy is fake," said Damon Barrett, deputy director of the charity Harm Reduction International. "The differences have been there for a long time, but you rarely get to see them. It all gets whittled down to the lowest common denominator, when all you see is agreement. But it's interesting to see now what they are arguing about."

The current review, taking place in Vienna at the UN Commission on Narcotic Drugs, comes after South American countries threw down the gauntlet to the US at this year's Organisation of American States summit meeting, when they argued that alternatives to prohibition must be considered.

Countries such as Colombia, Guatemala and Mexico have become increasingly critical of the UN's prohibition stance, claiming that maintaining the status quo plays into the hands of the cartels and paramilitary groups.

The draft reveals that Ecuador is pushing the UN to include a statement that recognises that the world needs to look beyond prohibition. Its submission claims there is "a need for more effective results in addressing the world drug problem" that will encourage "deliberations on different approaches that could be more efficient and effective".

Venezuela is pushing for the draft to include a new understanding of "the economic implications of the current dominating health and law enforcement approach in tackling the world drug problem", arguing that the current policy fails to recognise the "dynamics of the drug criminal market".

Experts said the level of disagreement showed fault lines were opening up in the globally agreed position on drug control. "Heavy reliance on law enforcement for controlling drugs is yielding a poor return on investment and leading to all kinds of terrible human rights abuses," said Kasia Malinowska-Sempruch, director of the Open Society Global Drug Policy Program. "The withdrawal from the most repressive parts of the drug war has begun – locally, nationally and globally."

Attacking the status quo is not confined to South American countries, however. Norway wants the draft to pose "questions related to decriminalisation and a critical assessment of the approach represented by the so-called war on drugs". Switzerland wants the draft to recognise the consequences of the current policy on public health issues. It wants it to include the observation that member states "note with concern that consumption prevalence has not been reduced significantly and that the consumption of new psychoactive substances has increased in most regions of the world". It also wants the draft to "express concern that according to UNAids, the UN programme on HIV/Aids, the global goal of reducing HIV infections among people who inject drugs by 50% by 2015 will not be reached, and that drug-related transmission is driving the expansion of the epidemic in many countries".

The EU is also pushing hard for the draft to emphasise the need for drug-dependence treatment and care options for offenders as an alternative to incarceration.

"Drug users should be entitled to access to treatment, essential medicines, care and related support services," the EU's submission suggests. "Programmes related to recovery and social reintegration should also be encouraged."

Ann Fordham, executive director of the International Drug Policy Consortium, said the draft revealed there was growing tension over the global drugs policy. "We are starting to see member states break with the consensus about how we should control drugs in the world. Punishment hasn't worked. All the money spent on crop eradication hasn't had the impact we would like to see."