Four people convicted of manufacturing methamphetamine in a rented Northland bach have been jailed for a total of nearly 35 years.

Kimberley Gibbons-Hurinui, 32, Jeffery Hall, 35, Tama Watene-Toi, 52, appeared for sentencing in the Whangārei District Court on Friday after they were found guilty by a jury in April.

Each was 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 in Dolphin Pl, on the Tutukaka Coast, on July 10, 2016, was busted 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.

Crown prosecutor Jarred Scott told the jury the Gibbons-Hurinui, Watene-Toi and Hall relied on the bach's isolation in that it was set back from the road with a bay in the background, to manufacture a lot of meth.

The bach owners lived in Australia and had contracted letting agency Coastal Holiday Homes to manage the property on their behalf.

On July 6, 2016, Hall called the letting agency to inquire about renting the bach and said he would pay cash but he was told to book online and pay by credit card.

Once the booking was made and $2600 paid for nine nights, a female employee of Coastal Holiday Homes tried to get hold of Hall to make arrangements to drop off firewood at the bach.

Three days later, the woman went to the bach and saw things that seemed out of place.

Windows were covered with blankets and bedsheets that didn't belong to the bach.

She heard a sound similar to that of a pressure cooker going off and smelled something.

She left the property and called police.

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.

Judge Keith de Ridder sentenced Roberts to 10-and-a-half years in prison, Watene got 12-and-a-half years, Hall 10 years and Gibbons-Hurinui 22 months with leave to apply for home detention.

Judge de Ridder neither imposed minimum periods of imprisonment nor ordered reparation as the four wouldn't have any means to pay given the length of their custodial sentences. He ordered the forfeiture of all items seized.