"We will act on any information we receive. Avocados are in season and it's important we get any reports of suspicious activity as soon as possible so we can follow it up," she said.
Anybody offered cheap avocados is also urged to contact police.
There had been a number of thefts from avocado orchards in Northland this year and previous years, with one Whangarei grower estimating $100,000 worth of fruit has been stolen over the past five years.
Growers were being urged to report all fruit thefts to police, increase security and inform other growers.
In November six quad bikes and 1000 avocados were stolen from a Maungatapere orchard while in August two Northland men allegedly selling stolen avocados at an Auckland market were arrested, and hundreds more fruit were discovered in a police raid on two Whangarei homes.
In August Whangarei police issued a health warning after 2000 avocados were stolen from a Maungatapere orchard over two nights after being sprayed with chemicals.