The Victorian senator is on a self-funded, fact-finding mission, meeting   policymakers and program developers in the European country.

Since 2001, drug users in Portugal are no longer put through the criminal justice system.

The funds saved from enforcement have been used to increase access to drug treatment and prevention, including rehabilitation services, in the country.

"Individuals [in Australia] who get into trouble with their drug use wouldn't be subject to criminal penalties," Dr  Di Natale said.

"Instead they would front a health panel which gets them into treatment and helps them with other things like housing and employment support."

Dr Di Natale said there had been no increase in drug use in Portugal since the reforms were introduced.

"Instead what we've seen is a huge decline in all the things associated with harmful drug use," he said.

"We've also seen more people in treatment, fewer drug overdoses, fewer cases of HIV and a decrease in crime."

Dr Di Natale made it clear Portugal had not legalised drugs, with law enforcement still targeting drug dealers.

The Greens leader is co-convenor of the Australian Parliamentary Group on Drug Law Reform, a cross party group of about 100 state and commonwealth MPs.

Liberal member for Murray Sharman Stone, another co-convenor of the group, said Australia's current drug policy was not working.

"We need to look very carefully at what other countries are doing, where they have focused on taking what we'd call illicit substances, where they look at them as a health problem," Ms Stone said.

"We'd put the criminals out of business in relation to those drugs."

Ms Stone said Australia did not have any real capacity to rehabilitate people from drug addiction.

"How many more babies have to be born brain-damaged, how many more women have to be killed by their intimate partners, we have two a week being killed right now, we had that horrific case of that mother in Brisbane where a number of those children were killed," she said.

"Just how long do we wait? When is the magic number?"

Ms Stone said she did not know what other members of her party would feel about the approach.

"I'm sure there would be a whole range of views, but I know we are united… with a deep concern about the impact of both alcohol and drugs," Ms Stone said.

Labor's co-convenor of the parliamentary group, member for Fremantle Melissa Parke, was overseas and unable to comment on Sunday.

Her spokesman, Josh Wilson, said Ms Parke supported a bipartisan approach to treating drug use as a health issue, rather than a crime.

"The Prime Minister is right in saying that the war on drugs is unwinnable so we need to bring together the best minds in the country to explore alternative models," she said in an earlier press release.

Victoria Alcohol and Drug Association chief executive Sam Biondo said Australia needed to build on its progressive stance towards drugs.

"There has been developments internationally that we can also learn from and consider," he said.

"There is a growing awareness of the failure of the war on drugs."

Mr Biondo said policies where funds were directed into the community and out of "failed" prison systems had been shown to be effective.

"We continue to pursue inappropriate policies that aren't cost effective and are creating a greater impost on the overall community and a negative impact for individuals and their families," he said.