Prohibiting the use of drugs in the Northern Territory has failed, Assistant Minister Jeff Collins says, and he will push the Government to look at decriminalising personal use quantities of drugs.

Assistant Minister for Police, Fire and Emergency Services, Jeff Collins, is currently in Portugal on a study tour, examining at that country's successful drug decriminalisation program.

"The prohibition model hasn't worked, people still use [drugs]," Mr Collins said.

"I'm not suggesting in any way that using the drug is a good thing to do, or that we should encourage it, but what we do need to do is look at those people who do use that drug as having a health issue, not necessarily a criminal issue."

He stressed that decriminalisation of drugs was a separate matter from legalising their use.

"Legalisation brings with it a whole raft of issues about supply and regulation and even taxation to some degree and the government's involvement, whereas decriminalisation is more specifically directed at drug users and treating them as a health issue as opposed to a criminal issue," he said.

Dramatic turnaround for Portugal

Portugal has experienced a dramatic turnaround since it decriminalised drug possession for personal use in 2001.

Personal use is defined as a 10-day supply of a drug. When a person is caught, they are referred to a commission for the dissuasion of drug addiction, which consists of a doctor, a social worker and a lawyer who decide what penalty, if any, that person may face.

However, four in five cases are suspended, with no action taken.

Individuals may be prescribed counselling, drug substitution treatment, or face civil penalties such as fines.

A report by the global drug regulation network Transform found that in Portugal, adult drug use has decreased since 2001, young people aged 15-24 are using fewer drugs, and the prevalence of drug-related infectious diseases such as HIV and hepatitis had dropped.

Portugal also has the second-lowest rate of drug-induced deaths for any country in the European Union: three deaths per million citizens, compared to a European Union average of 17.3 deaths per million citizens.

However, it is still illegal to possess trafficable or commercial quantities of drugs.

Treatment better than incarceration: Collins

Mr Collins said he would be pushing for the NT Government to decriminalise at least some types of drugs, and also to look at how the Portuguese model might work to reduce alcohol abuse.

He said he would also be meeting with health professionals while in Portugal to see how the treatment system worked, noting the number of people in voluntary drug abuse treatment had increased in Portugal.

"I think that's a good thing," he said.

"You've got roughly the same number of people using drugs, but you have more people in treatment, so if that's an end result of the system - getting them into treatment as opposed to getting them into incarceration - then, for me, that's a successful program."

The Australian Medical Association of the NT said the former NT Government had defunded rehab programs and the drug court, and said any decriminalisation should be done "with extreme caution and with substantial funding increases for both mental health and rehab", president Robert Parker said.

He said there would likely be an increase in drug-related mental illnesses, which would need to be planned for, and said there were massive health implications for Aboriginal people, who make up a third of the NT's population.

"Given the vulnerability factor, it will probably have a major impact on mental health in Indigenous communities," he said.

He said the rate of drug-induced psychosis for Indigenous people was three times that of the non-Indigenous community in the NT, and that it was difficult to establish effective rehab programs in remote areas.

"A lot of Indigenous people don't engage in rehab," he said.