Commodity prices fell to a 15 month low in March.
The ANZ Commodity Price Index fell 1.7% last month, to its lowest level since December 2010.
ANZ economist Steve Edwards says the index is now 8.5% lower than at this time a year ago.
"There's been a fall in 11 of the 17 commodities that we measure, the largest being a drop in the price of pelts, but also it was followed up by falls in the price of dairy goods, lamb, aluminium and venison", he says.
When converted back into New Zealand dollars, returns at the farm gate declined 0.2% due to a lower New Zealand dollar.