Merchandise terms of trade index fell slightly in the June quarter, the first fall in two years, following a 34-year high in the first quarter.
The index fell 0.5% but is still at its second-highest level since the March quarter of 1974.
Export prices were up 4.4%, while export volumes fell 3.7% as dairy exports continue to be hit by the drought.
At the same time, the import price index rose 4.8%, mainly due to high oil prices, while volumes were up 5.4% due to an oil rig and platform being imported.
UBS Investment Bank senior economist Robin Clements, says the drop was smaller than expected, but is a sign of things to come.
He says the sharp reduction in dairy volumes suggests Gross Domestic Product for the second quarter may be weaker than current predictions of 0.3%.
