Two Fonterra shareholders and former board members say a lack of confidence in the company is pushing suppliers towards competitors.
Greg Gent and Colin Armer are seeking shareholder support to reduce the number of Fonterra board members from 13 to nine.
Mr Gent said suppliers were leaving the company and a governance restructuring was required to restore confidence in New Zealand's biggest company.
"You know, Fonterra's share of the New Zealand milk supply is falling quite fast and there are competitors out there who have actually got waiting lists to take additional supply so, yes, that concerns me," he said.
"Everything in an organisation starts at the top. A more dynamic, faster reacting board will help and that flows through."
Fonterra has not responded to Mr Gent's comments about supplier numbers.
Meanwhile, the six candidates standing for election to the co-operative's board of directors have been announced: Murray Beach, Greg Maughan, Blue Read, Nicola Shadbolt, Ashley Waugh and John Wilson.
Voting papers will be sent to shareholders on 30 October and the voting period will close on 23 November, with the winners announced that day.