A surge in imports and rise in oil prices have led to a record monthly trade deficit.
Official numbers show a deficit of $1.48 billion for August as imports came close to record levels with more money spent on oil and cars.
August is usually the weakest spot for exports because agricultural production has yet to pick up after winter.
The annual trade deficit worsened to $4.8b, the biggest since February 2009.
ASB senior rural economist Nathan Penny said monthly figures can be volatile, but he expected an improvement.
"In particular, agricultural production has started the new season on positive note on the back of favourable growing conditions and supportive prices in New Zealand dollar terms."
The New Zealand dollar has fallen 3 percent so far this year against the currencies of our main trade partners, which lifts the value of export earnings but also raises the cost of imports.
Mr Penny said the annual deficit should narrow gradually, and while imports were higher, much of the spending was on capital goods needed by businesses, rather than on consumer items.
He said one cloud on the trade horizon was the US - China dispute, where the world's two biggest economies have been imposing tariffs on each other's goods.
"The key risk is that demand for New Zealand exports slows as the trade tensions weigh on global sentiment and then global growth."