Fonterra says farmers are responding to a lower forecast farmgate milk price by pulling back on milk production.
Fonterra has maintained its milk volume forecast for the 2015/16 season, which is about 2-3 percent lower than the amount collected last season.
But it warns there could be a further downward revision of forecast volumes as the season progresses, with many farmers advising they expect significant milk volume reductions.
Fonterra's forecast payout for this season sits at $3.85 and the co-operative is due to release its annual results on 24 September.
