The ANZ's index of international commodity prices last month recorded its broadest fall in prices since the series started more than 20 years ago.
Every commodity, except apples, recorded a fall in December, ANZ economist Steve Edwards said.
That represented the broadest monthly drop in commodity prices measured across the New Zealand export basket since the series started in 1986.
The ANZ commodity price index recorded a 7.4 percent fall in the price of the basket in December, the fifth consecutive monthly drop in the series. The index is now 27 percent below its peak last July.
Pelt prices recorded the largest drop in December, slumping 62 percent from November to a new record low, Mr Edwards said.
Aluminium prices fell 20 percent to a five-year low, while wool and dairy prices both fell more than 12 percent.
Dairy prices were now at the level they were two years ago, before the start of the much heralded surge 18 months ago.
Wool prices had dropped for six successive months and were now only 2 percent above the lowest level recorded by the series since 1986, Mr Edwards said.
Log prices were down 4.4 percent, wood pulp prices down 3.7 percent and sawn timber prices down 2.2 percent.
Seafood and lamb prices both eased 2.4 percent, while venison and beef prices each dropped 1.4 percent.
In New Zealand dollar terms the index fell 6.1 percent last month, but is just 8.1 percent down on its peak of four months ago, and is now back to its level of a year ago.