Coppas are busting backyard bud growers

Police are anticipating a bumper crop of cannabis - and are giving Aucklanders the green light to contact them about any dodgy gardening behaviour around their properties.

Home gardens are flourishing after a wet spring, and there are concerns some plants might be flourishing that shouldn't be.

Detective Sergeant Tim Williams adds people should keep an eye on their own backyards.

"It is a common tactic for growers to grow on neighbouring and public land, the reason for this is they believe they're less likely to be held accountable. But if this is occurring on anyone's land without your consent, definitely contact the police," he says.

Police warn cannabis cultivation often has a wider effect on crime in an area, provoking thefts, burglaries, robberies and violence.

"The rural community is especially where this happens. Northern Rodney, that sort of area on the islands on the Hauraki Gulf and the rural south Auckland areas are common areas as well," he says.

"This is the time of the year when criminal offenders are going into the bush and planting their crops in the outdoors. Often done in the start of spring right through to Christmas period."