Police have taken 185 people into custody after finding 14,000 cannabis plants and 13 kilos of drugs on the East Coast of the North Island during a major drug bust.

Twenty-six properties in Napier and Hastings were searched after police spotted a large number of cannabis plants growing in back yards during a fly over.

A total of 210 rural and urban properties were searched from central Hawke's Bay up to the East Cape during the operation.

A team of 30 police officers found 35 firearms, including shotguns, sawn-off shotguns, hand guns and 22s, at several houses where drug offending was taking place, and a small amount of cocaine in one house.

Police said many of the people taken into custody would face charges of supplying cannabis, cultivating cannabis, manufacturing cannabis oil, possession of cocaine and firearm offences.

Head of the Eastern Organised Crime Group, Detective Senior Sergeant Mike Foster, said the bust dispelled the myth that cannabis was usually grown in rural areas away from the public's gaze.

"Cannabis growers will take their chances anywhere and we rely heavily on the public to tell us if they see anything suspicious in their neighbours' properties.

"While some of these plants were reasonably well hidden, some were in quite open view and would have been noticed easily. We urge people to contact us if they find or see anything to do with drug activity."

Foster said police were pleased with the results of the operation and there would be an ongoing focus on cannabis crime throughout the district.

"These cannabis operations always achieve good results, but it doesn't end there. We are constantly monitoring the activities of drug offenders and associated criminals. There will be no let-up."

In Wairoa, police searched six properties where cannabis and firearms were found and arrested five people on cannabis and firearms charges.

Police searching a property in Gisborne found 430 mature plants growing in a back orchard, and a sophisticated grow room set up in a haybarn.

Foster said the trend towards indoor growing was increasing and each year police were finding more indoor growing operations.

"These are usually quite sophisticated and well-hidden. Many cannabis growers are leaning towards this type of growing to try to avoid detection by police."

He said there was a definite link between drug offending and burglary, with many drug offenders committing burglaries to fund habits or pay drug debts.

"It is in the interests of the community to report any suspicious activity related to either drugs or burglary.

"The two are intertwined and if we can stem either or both types of offending, the community will benefit from it," Foster said.

Anyone with information about cannabis or other drug activity was urged to contact police.