The country's purchasing power against the rest of the world has fallen from a 37-year high, due partly to a high New Zealand dollar.
Official figures show the terms of trade declined 0.7% in the three months to September, meaning fewer imports can be bought for every dollar of exports sold.
The terms of trade rose to their highest level since 1974 in the June quarter, driven by strong demand and prices for dairy products.
However, a surging New Zealand dollar has dampened import and export prices.
Export prices dropped 4%, reflecting decreases in dairy products, forestry and meat while import prices fell 3.4%.
Volumes have also been affected.
Exports fell, although Statistics New Zealand says they remain at high levels, with declines in the volumes of meat, pleasure boats and logs offsetting a rise in dairy products.
Import volumes rose, led by stronger capital goods such as plant and machinery.
On an annual basis, the terms of trade rose 3.3%.
The effect of Europe debt crisis on global growth is likely to lead to further declines in the country's purchasing power against the rest of the world.
UBS senior economist Robin Clements says an appreciating dollar dampened export prices by more than import prices during the period.
