Imports fell last month for the first time since August 2007.
Statistics New Zealand says a drop in the number of cars being imported in January was a key reason for the 0.9% fall in the value of merchandise imports to $32 million.
The decrease in imports compared to January 2008 was led by passenger motor cars, which fell $105 million.
This was partly offset by a $91 million increase in petroleum and products.
Merchandise exports were valued at $3.2 billion, up $92 million or 3%, compared to January 2008.
The monthly trade balance for January was a deficit of $187 million.
As a percentage of exports (5.9%) it was the smallest deficit for a January month since 2001.