"We need help from the public to point us in the direction of these drug cultivations and to bring offenders before the courts," Mr Foster said.
In past cases farmers had been oblivious to scattered cannabis plots being set up on their land and had stumbled upon them by chance.
Other plots had been discovered by hunters and outdoor enthusiasts who ventured into isolated bush regions.
Some had also been found amid residential gardens hidden from the road.
Mr Foster said it was incumbent on everyone to report any suspicious activity to police.
"Drug offending drives other crime such as burglary and vehicle theft and this affects many people within the Eastern District."
Earlier this year police staged Operation Turner across Hawke's Bay and Gisborne that resulted in 16 arrests after 19 properties were searched and more than 170 cannabis plants, dried cannabis and "tinnies" were uncovered.
Two years ago police launched a major cannabis offensive called Operation Linda across the Bay and East Cape that led to 15,077 plants being destroyed, 144 arrests made and nine firearms found.
Police said indoor cultivation would also be taking place and while country people were asked to look for rural signs city residents were asked to look for the urban ones.
People should contact their local police station or information could also be left anonymously on Crimestoppers - 0800 555 111.