New Zealand-based dairy cooperative Fonterra Co-op Group Ltd. said July 27 that John Wilson will step down as chairman effective immediately due to his health concerns.

Wilson, who underwent surgery last month, will remain the cooperative's director until he retires from the board at Fonterra's annual general meeting in November.

"I have made a very good recovery and am well but will need on-going treatment. Continuing as chairman when I cannot put my full energy and attention into the role is not appropriate," Wilson said.

The company added that John Monaghan, who has been a Fonterra director since 2008, will replace Wilson in the role.