Canada is poised to legalise recreational marijuana across the country this week, making it the first G7 country to do so.

The Canadian Senate is due to vote on Thursday on bill C-45, which would legalise the use and purchase of marijuana for people over 18. The bill has already passed the House of Commons, and is supported by Prime Minister Justin Trudeau. The Senate has studied the bill for six months and is expected to pass it.

Sales of legal cannabis will not be permitted until two to three months after the legislation passes, the country’s health minister has said.

Canada would be the first of the G7 countries – a group of seven of the world’s largest economies – to legalise the drug nationwide. Some of the countries, including Canada, have passed legislation allowing marijuana for medical use. Several US states have legalised recreational use of the drug.

Becoming a leader in legalisation could have major impacts on Canada’s economy. Legal marijuana is expected to me a more than $6bn business, according to a report by financial services company Deloitte, with $4.3bn coming from recreational sales and $1.7bn from medical.

In pictures: 4/20 Marijuana world rallies Show all 26 1 /26 In pictures: 4/20 Marijuana world rallies In pictures: 4/20 Marijuana world rallies A man wears a marijuana leaf mask during the annual 4/20 cannabis culture celebration at Sunset Beach in Vancouver, British Columbia AP In pictures: 4/20 Marijuana world rallies A lady smokes marijuana on Parliament Hill on 4/20 in Ottawa, Ontario Getty Images In pictures: 4/20 Marijuana world rallies James Reed smokes a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies People sign a 4/20 sign on Parliament Hill on in Ottawa, Ontario Getty Images In pictures: 4/20 Marijuana world rallies A woman smokes marijuana on Parliament Hill on 4/20 in Ottawa, Ontario. Polling released showed strong support in Canada for a government drive to legalise recreational use of marijuana, but many would like the proposed minimum age for consumption to be raised. Sixty-three percent of respondents told the Angus Reid Institute they support legalisation Getty Images In pictures: 4/20 Marijuana world rallies A man smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada Reuters In pictures: 4/20 Marijuana world rallies Demonstrators smoke marijuana during the '4/20 Santiago' rally in favour of legalisation in front of the La Moneda presidential palace in Santiago, as part of the Global Marijuana March which is being held in hundreds of cities worldwide Getty Images In pictures: 4/20 Marijuana world rallies People play with a mock marijuana joint during a 4/20 party to demand legalisation and to celebrate marijuana culture outside the Senate building in Mexico City, Mexico Reuters In pictures: 4/20 Marijuana world rallies Adam Eidinger, co-founder of DCMJ, hands out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC Getty Images In pictures: 4/20 Marijuana world rallies In pictures: 4/20 Marijuana world rallies Police arrest Rachel Ramone Donlan after she handed out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC AFP/Getty Images In pictures: 4/20 Marijuana world rallies Police arrest Rachel Ramone Donlan after she handed out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC Getty Images In pictures: 4/20 Marijuana world rallies Thousands of people gather to smoke marijuana during the '420 Santiago'rally in front of the La Moneda presidential palace in Santiago Getty Images In pictures: 4/20 Marijuana world rallies People attend the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Kevin Barron and Lasean Moore of Raleigh, North Carolina, share a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Nic Ruhl takes a pull on a giant hand rolled joint at precisely 4:20pm MDT during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Various cannabis paraphernalia on display at a vendor's stall during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Mo Banez, of Austin, Texas, lights a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies A man displays a large container of cannabis during the Denver 420 Rally at Civic Center Park in Denver, Colorado. The rally, held annually, is a celebration of both the legalisation of cannabis and cannabis culture. Colorado is one of twenty-six U.S. states along with the District of Columbia that has legalised the use of cannabis either recreationally or medically AFP/Getty Images In pictures: 4/20 Marijuana world rallies Sitting in small groups on mats shaded by trees in the Rose Garden just across from the Knesset, participants lit up as the clock struck 4:20 for the local version of the traditional worldwide April 20 pro-marijuana events, known as '420' rallies Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem during a rally at the Rose garden Getty Images In pictures: 4/20 Marijuana world rallies Sitting in small groups on mats shaded by trees in the Rose Garden just across from the Knesset, participants lit up as the clock struck 4:20 for the local version of the traditional worldwide April 20 pro-marijuana events, known as '420' rallies Getty Images In pictures: 4/20 Marijuana world rallies An Israeli girl poses with a mock marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current laws Getty Images In pictures: 4/20 Marijuana world rallies aelis pass around a marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current laws Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current law Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem on April 20, 2017 during a rally opposite the Knesset to celebrate 420 and express defiance of current laws AFP/Getty Images

Legal cannabis will be heavily regulated, however. Under guidelines from Canada’s public health agency, marijuana products will be sold in plain packaging with limited branding. Packaging will include a yellow health warning and a red stop sign indicating that the product contains cannabis, as well information on the particular strain and THC content.

Under the current legislation, adults will only be allowed to carry up to 30g of dried cannabis. Exceeding this amount in a public space – including an individual's own vehicle – will be punishable by up to five years in prison.

Driving under the influence of cannabis will also be highly punishable. The current proposal puts the penalty for a first offence at a minimum $1,000 fine, with a minimum of 30 days imprisonment for a second offence. Third and subsequent offences will be punishable by a minimum of 120 days.

Oregon is producing three times more marijuana than it can consume

The details of the legalisation effort will be handled at a provincial level. Some provinces, for example, plan to ban home cultivation of marijuana, even though the current legislation allows for it on a federal level. Provincial law also varies widely on smoking in public, according to CTV News.

"We've had to amend our zoning here in the city in order to accommodate retail stores, we've had to adjust our business licensing, and amending our smoking and vaping bylaw," Matt Zabloski, the City of Calgary's project lead for the legalisation of cannabis, told CBC News.