Statistics New Zealand released its trade data on late Monday evening. New Zealand's trade deficit widened to NZ$1,222 million in September from NZ$1,079 million in August. August's figure was revised up from a deficit of NZ$1,035 million.
Analysts had expected the deficit to decline to NZ$800 million.
Exports rose 2.0% year-on-year in September, while imports decreased by 1.2%.
"The value of imports from China has increased across most commodities for the last 12 months. Mobile phones and laptops led the increase, up a quarter of a billion dollars," Statistics NZ international statistics senior manager Jason Attewell said.