Rich Lister and former 'Ice Cream Queen' Diane Foreman has accused Fonterra of being arrogant in its business dealings.
Ms Foreman's Emerald Food Group owned the New Zealand Natural ice cream brand that had franchised outlets in 33 countries.
She says she was approached by a Chinese buyer in 2013, but before she started negotiating, she thought dairy cooperative Fonterra might be interested.
Ms Foreman claims she emailed a director, and when there was no reply, approached Fonterra through another advisor and was told there was no interest.
"I am not saying they should have bought it, it might not have been a good fit, but they didn't show any interest at all and that's what I am calling arrogant," she said.
Fonterra has long-held a desire to move more into value-added products, like cheese, infant formula and even ice cream. The cooperative already owns ice cream companies Tip Top and Kapiti. With raw milk prices tanking, the debate about value-added products has reared its head again.
Ms Foreman says many years ago Tip Top did show some interest in New Zealand Natural, but there was nothing recently. In the end, she says, the company was sold to a Chinese textile manufacturing family. Ms Foreman says the new owners plan to rapidly expand the company in China.
A Fonterra spokesperson said the company was interested "but weren't provided with any information on which to make a decision".
But Ms Foreman she was never asked to provide any information by Fonterra.
Ms Foreman has just published her latest book In the Arena which she describes as a toolkit for entrepreneurs.