Police officers who discovered a meth lab in a Northland holiday home "were trespassers from the moment they stepped on the property", a lawyer says.
One of four people jailed for making meth in the Dolphin Place bach is appealing his conviction on the basis police trespassed on the property and the evidence was "improperly obtained".
Jeffery Hall, 36, was convicted and sentenced in 2018 to 10 years in prison for his role in the drug offending, after being found guilty by a jury in the Whangārei District Court.
In the Court of Appeal in Wellington today, his lawyer Mark Ryan said police could not rely on "implied licence" to justify going onto the property.
Implied licence allows police or any other person to enter a property and knock on the front door. For example, a girl guide selling cookies would be allowed this form of entry.
But Ryan said police attended a "briefing" and armed themselves before visiting the isolated bach, and road spikes were prepared at the end of the road.
"The police were in investigatory mode prior to setting foot on the property. They went there to search," Ryan said.
"It was a home invasion."
The fact they were there to investigate immediately took away the implied licence, meaning they were trespassing, he said.
"What follows from there is that all of what they discovered is discovered as trespassers, and is improperly obtained."
Crown lawyer Mark Lillico said police knew there was a possibility there could be a meth lab on the property but that did not negate their ability to go to the door for investigative purposes and communicate with the occupants.
He also said they were "quite entitled" to protect their safety by arming themselves.
Hall and his co-offenders, Kimberley Gibbons Hurinui, Tama Watene-Toi, were each charged with manufacturing meth, possession of equipment with an intention of manufacturing meth, possession of meth for supply, unlawful possession of a restricted weapon, unlawful possession of a pistol, unlawful possession of a firearm and unlawful possession of an explosive.
The meth lab on the Tutukaka Coast was busted in 2016 after a property manager became suspicious and called police.
All three were found guilty of manufacturing meth while Watene-Toi was also found guilty of possession of equipment with an intention of manufacturing meth.
Guilty verdicts were also returned for Hall on charges of possession of equipment, possession of a shotgun and possession of ammunition. The jury found them not guilty on the remaining charges.
A fourth person, Julian Roberts, 44, pleaded guilty to three charges of possession of a firearm and single charges of possession of equipment, manufacturing meth and possession for supply of meth.
At the bach, police found 332g of meth and 1.2 litres in liquid form in two containers and in 11 bags with a total yield of nearly 1kg of meth.
The Court of Appeal judges have reserved their decision.