Cadbury is warning that Moro bars could taste a little different from today.
Moro bars previously made at the company's Dunedin factory are now being made in Australia.
Cadbury NZ managing director Matthew Oldham said yesterday that making a chocolate bar in a different factory "is like making a cake in a different kitchen".
"You can't always guarantee it will turn out exactly the same."
Moro is not the first Cadbury product to be moved overseas.
The company has already upset chocolate-lovers by switching to British-made Creme Eggs, and there was growing irritation last night.
"Cadbury needs to be boycotted to the extreme," wrote one person on the Trade Me message board. "We are the customers, but we seem to be getting screwed in broad daylight."
Another wrote: "Cadbury is or was a NZ icon. Well, not any more. Bye bye, Cadbury, we are defecting!"
Mr Oldham said the production changes were essential to securing the future of the Dunedin factory and hundreds of jobs. The first batch of Australian-made Moro will be 60g bars, and 85g twin packs and share-packs will arrive on shelves during the next few weeks.
Mr Oldham was accused online of betraying New Zealand.
It is the latest in a long line of confectionery changes in the past year. Paddle Pop icecreams have shrunk, Cadbury already reduced some chocolate blocks from 250g to 200g, while Mars reduced its Mars bars from 60g to 53g and Twix from 58g to 53g, and also produced smaller bags of M&Ms, Pods and Maltesers.
Meanwhile, Tip Top reduced the size of four of its specialty icecream tubs from 2 litres to 1.6 litres.
And not only sweet treats have been affected - Anchor reduced its cheese blocks from 1kg to 900g.
Mr Oldham said the Dunedin factory would continue making products including boxed chocolates such as Roses and Milk Tray and favourites such as Pinky and Marshmallow Eggs.
It will soon also be making Turkish Delight for the New Zealand and Australian markets.