A police spokesperson said 35 firearms were uncovered at houses where drug offending was taking place.
They included shotguns, sawn-off shotguns, hand guns and 22s.
Thirty police staff searched 210 properties in rural and urban areas.
Head of the Eastern Organised Crime Group, Detective Senior Sergeant Mike 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," he said.
A decision to fly over Napier and Hastings suburbs proved lucrative, with a large number of cannabis plants growing in back yards being spotted from the air.
That resulted in a number of drug dealing houses being searched, many with large quantities of cannabis inside ready for sale.
Mr Foster said the city cannabis activity 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 neighbour's 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."
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. There was also a sophisticated grow room set up in a haybarn on the property.
Mr 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. Once again, we need to hear from people who notice any strange behaviour in their neighbourhood or rural area."
Anyone with information about cannabis or other drug activity should contact their nearest police station, or information can be left anonymously on Crimestoppers 0800 555 111.