Michael Spaans has stepped down from the board of Fonterra due to ill health, effective from today, the co-operative said.
Ian Farrelly, who retired as a director last December, has agreed to fill in for Spaans until this year's annual meeting.
Chairman John Wilson said Spaans' contribution to the New Zealand dairy industry had been significant, both inside and outside the Fonterra boardroom.
Spaans, a dairy farmer, came up through the ranks, spending time on the then New Zealand Dairy Group's shareholder council and then the Fonterra Shareholders' Council, before building his governance experience outside the industry.
"As a result, his insights and experience are invaluable, particularly on Fonterra's Milk Price Panel, Audit and Finance Committee and the Co-operative Relations Committee," Wilson said in a statement.
Spaans may consider standing again for the board if he is given a clean bill of health, Fonterra said.