The number of crimes involving cannabis has spiked in the parts of NSW that surround Canberra, defying a state-wide trend as the ACT looks increasingly likely to legalise the drug.
But a strategic policing and law enforcement expert does not believe legalising cannabis in Canberra would lead to a further increase in related crimes in nearby areas of NSW.
New data from the NSW Bureau of Crime Statistics and Research shows a 5.6 per cent drop in cannabis-related offences across the state, when the period from April 2018 to March 2019 is compared with the same timeframe in 2017-18.
But in the capital region of NSW, which is made up of eight council areas near the ACT including Queanbeyan-Palerang and Yass Valley, cultivation of cannabis was up 32.7 per cent. Dealing and trafficking in cannabis offences increased by 133 per cent, and possession and/or use of cannabis offences jumped 11.4 per cent.
The increase in cannabis-related offences just across the border comes as members of the ACT Legislative Assembly are being urged to allow Canberrans to legally grow up to four cannabis plants each, or six per household.
Two of the three members of an Assembly committee examining Labor backbencher Michael Pettersson's bill to legalise the drug for personal use in the ACT last week recommended some changes, including increasing the number of permissible plants per person from two to four, and said the bill should be passed.
NSW Police declined to comment on whether it was concerned that people legally cultivating cannabis in the ACT could take it across the border and further increase the number of cannabis-related crimes recorded in the capital region.
Dr John Coyne, a policing and law enforcement expert from the Australian Strategic Policy Institute, said any impact the proposed changes to ACT law would have on surrounding NSW was likely to be "negligible" because of the strict limits on the number of plants and the type of growing set-ups that would be allowed.
"If you've got a giant hydroponic set-up in your house [in Canberra], the police are still going to pursue you," he said.
"I don't think it's going to be a safe haven in the same way that we saw in the US in some states.
"What happened there was people were growing it in some of the more liberal states on the west coast and then driving across the border and selling it in the next state over, where it's illegal.
"I don't think that will be the case [here]."
Dr Coyne said the bill would likely achieve what it was intended to achieve, which was keeping people who did not need to enter the criminal justice system out of it.
He said if anything, legalising small amounts of cannabis cultivation for personal use in the ACT might lead to a decrease in its production in surrounding parts of NSW because of falling demand for illegally grown marijuana.
The biggest challenge, he believed, was sorting out how police would enforce laws relating to cannabis in the ACT if Mr Pettersson's bill was passed, given it would create a conflict with Commonwealth legislation.
"Canberra is the largest population centre in this region, with a large middle-class and high disposable income," Dr Coyne said.
"As a result of that, there would be a large demand for marijuana, amongst other drugs, within the Australian Capital Territory.
"In terms of usable space to grow marijuana, you would argue that if there's a large market here, people are going to grow it somewhere close, in districts around Canberra, to feed that market.
"So there's probably some scope for thinking that if the legislation were to go through and the difference between the Commonwealth and territory legislation was reconciled, you would see some decline in the production or the growing of marijuana in the NSW districts surrounding the ACT."
While it would become legal to cultivate certain quantities of cannabis in Canberra under the proposed new laws, private growers would still need to source cannabis seeds through the black market.