The trade deficit has widened due to a fall in dairy exports and lower oil sales.
Official figures show a deficit of $305 million in January, compared with a $161 million shortfall for the same month a year ago.
Exports fell 10% to $3.3 billion, led by milk powder, butter and cheese. Imports fell 6% to $3.7 billion.
Westpac senior economist Michael Gordon said the deficit was worse than expected, due to a combination of factors.
Mr Gordon said there were softer exports for the month with low volumes for oil and dairy products and there was a fairly sharp bounce in imports as well.
But Mr Gordon said imports of capital equipment grew which is a good sign as it suggests businesses are prepared to invest.
And he said there's more to come through in export earnings as dairy volumes are likely to be up about 1% on last season which should help the outlook going into the first half of this year at the least.
Mr Gordon said beyond that it will be a matter of what happens when demand in the economy recovers.
He said there will be a lot of imported materials needed for rebuilding Christchurch and that's likely to see persistant trade deficits through 2014.
On an annual basis, the deficit widened to $1.3 billion.