Legalising marijuana for recreational use would boost the budget by up to $1.8 billion a year, the Parliamentary Budget Office has revealed.

The independent costing of the policy submitted by the Greens shows a tobacco-style 25 per cent excise on each sale with a 10 per cent Goods and Services Tax and a reduction in law enforcement would net $3.5 billion by 2020-21.

Marijuana tourists travelling to Australia would add up to “10 per cent of total sales”, earning $130 million in revenue by 2020.

Greens leader Richard Di Natale said the boost would be used to fund drug education and treatment programs.

“The Greens see drug use as a health issue, not a criminal issue,” he said.

“Our plan to create a legal market for cannabis production and sale will reduce risks, bust the business model of criminal dealers and syndicates and protect young people from unfair criminal prosecutions.”

The PBO said the policy would allow the Australian Federal Police to “re-allocate a proportion of the resources currently directed at cannabis to strengthen the law enforcement of other illicit substances”, such as ice, methamphetamines and heroin. [Read more at The Sydney Morning Herald]