"We've made more stock in the hope that people can get it."
It is unknown which year Cadbury initially launched the Caramilk product as a permanent item in New Zealand, but it was available until 1994.
It was also unknown why it was discontinued, Kane said.
"It's a bit of a mystery as to why it stopped being made because looking back now it seems like it was a winner."
The company has donated 64 blocks to Paralympics New Zealand and Make A Wish Foundation to be auctioned off on Trade Me.
Planning and production for next month's sale began last year, Kane said.
"We knew pretty quickly in the middle of last year, when it sold really well and we were getting a lot of requests for bringing it back, so we were able to start sorting raw materials, different packaging and ingredients in the second half of last year, and then the actual production itself was around three weeks of continuous work."
Countdown Ponsonby store manager Brad Rossiter said the supermarket was anticipating the product to fly off the shelves, and would recruit an additional security guard to cope with demand.
"In all seriousness, as a retailer it's really exciting to see how much Kiwis love the product," Rossiter said. "We know when customers walk in the door they'll want to be able to find Cadbury Caramilk straight away so we'll need to have a display by the door piled high to meet demand."
Kane said there were no plans to bring Caramilk back permanently, but the idea could not be written off.
"At the moment we've made as much as we possibly can, and we can only manage to make enough stock for a short run - but never say never."