In the latest raid, fruit from about 80 trees had been stripped to a height of about 5m. She said over the last five years the theft of about $100,000 from her orchard had left her with no options.
"I'm going to sell up after this season. It's my livelihood but I feel I have no other choices."
She believed most of the fruit would be sold at markets in Auckland but some was being sold through businesses around Northland.
"If people continue to buy stolen fruit, people will keep stealing them," she said.
"People need to think about where the avocados have come from and make sure it's a legitimate source. Otherwise they might be helping those people who are stealing."
Fruit was still maturing and was not ready to be picked. If fruit was taken off trees early they lacked the oil content and although they turned black they tasted watery, she said.
Former NZ avocado grower representative Mike Eagles said growers needed to take extra on orchards as fruit neared maturity.
He said gates into orchards needed to be padlocked and any suspicious vehicles should be reported to police.
Growers in Bay of Plenty had also reported trespassers in orchards. Mr Eagles had spoken to Northland growers who had had fruit taken this season.
He also said if people were approached by anyone trying to sell car boot loads of avocados, take a description of the person and their vehicle registration and report the activity to police.
Police confirmed they were investigating the theft of avocados from the Whangarei woman and said late last month an orchard in Maunu had four large trees stripped of fruit and in May an orchard owner on Whatitiri Rd reported avocados had been stolen.
"Police take these thefts seriously. Growers put a lot of effort into producing the avocados and these thefts affect their livelihoods," police spokeswoman Sarah Kennett said.
Police urged growers to report any thefts and, if they or their neighbours notice any suspicious activity, they should call 111.
Also if anyone has any information relating to these thefts they can call Whangarei Police on 09 430 4500 or if they wish to remain anonymous call Crimestoppers on 0800 555 111.