The legalisation of cannabis in Canada has created jobs and revenue, improved safety and reduced illegal sales, according to officials.

Six months after the law was changed on 17 October, the most obvious effect has been a rise in prices, according to the latest government statistics, possibly due to shortages in supply.

“Legalisation has gone well,” a government official told Reuters news agency, under cover of anonymity.

It is now safer to be a consumer because of regulation, the official said, adding that black market sales are falling and legal jobs and revenue are being created.

Illegal sales of the drug decreased to 79 per cent of the total sales by the end of 2018, compared to 90 per cent the previous quarter.

There has been no indication of major spikes in crime or public health problems, according to a report by CTV News, although this may not become apparent for several months. The latest official crime statistics available only cover up to 2017.

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

However prime minister Justin Trudeau and his Liberal party have not yet openly sought to take credit for the policy ahead of the federal election in October. The issue is not a “primary focus”, according to the unnamed official.

Polls show the Liberals either level or falling behind the rival Conservative Party, whose leader Andrew Scheer has expressed concerns about safety, particularly around people driving while under the influence of cannabis.

“Canadians are accepting of legalisation, but I don’t think they’re celebratory,” said Peter Donolo, a communications director for former Liberal prime minister Jean Chretien.

Some major licensed retailers have reported losses for the first three months after legalisation, mostly because of soaring costs offsetting increased sales.

Other retailers have reported difficulties in getting started, and shops only opened in the province of Ontario, which includes the capital, on 1 April.

Mr Trudeau recognised the supply shortage in an interview with the Canadian Press but said he expects it to be resolved “during the coming months”.

At cannabis stores in Ottawa close to parliament, customers and retailers expressed their approval of legalisation.

“I live close by and I’m excited to see how this store will change the neighbourhood,” said Jessica, 23, who declined to give her last name. “I did not vote Liberal last time, but I might this time.”

Cheralynn, 55, said the promise to legalise marijuana was one of the main reasons she voted for Trudeau in 2015. “And I like Justin,” she added. “Most women do. He’s kinda cute.”

Michael Paterson, a license holder at one shop, said: “We have a deep appreciation for the opportunity we’ve been granted.”

Spending on legal cannabis in Canada is expect to grow from $598m (£342m) in 2018 to $5.2bn (£3bn) in 2024, according to a report by Arcview Market Research.

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Official statistics show 15 per cent of the population in Canada, including 19.4 per cent of men and 11.3 per cent of women, reported using cannabis during the last three months of 2018.