Dairy, meat and forestry exports led the rise, and exports to China were up 52% to $1.5billion in March, StatsNZ data showed yesterday.
The market had expected a $131million surplus and the ASB $100million, ASB's senior rural economist Nathan Penny said.
"We expect stronger dairy exports values to lift the underlying trade balance over 2019," Mr Penny said.
Export values hit a record high for a month, he said.
"Export values were strong across the three main export categories of dairy, meat and forestry.
"Dairy and meat export values both surged 7.4% on top of strong February outurns," he said.
While total goods exports lifted 19% to $5.7billion last month from March 2018, imports for the same period shrank 3.5% to $4.8billion.
StatsNZ international statistics manager Tehseen Islam said: "Exports to China were the leading contributor to increases in several primary sector commodities including dairy products, beef, lamb, and forestry products."
Westpac senior economist Michael Gordon said the "whopping" $922million trade surplus was much stronger than market forecasts and well above even Westpac's "top-of-the-market pick of $400million".
"Part of the improvement in March was seasonal, with exports usually nearing their peak at this time of year.
"There was a strong lift in volumes for both dairy and meat, along with growth in wood, fruit and oil exports," he said.
"This was an exceptionally strong month for exports, and we would expect some reversal in April.
"That said, the sharp rise in dairy export prices in recent auctions, which will more than offset lower volumes, has yet to come through in the trade figures," Mr Gordon said.
Exports of dairy products led the overall rise in exports, up 22% to $1.4billion, led by milk powder, up $226million from a year earlier, Mr Islam said.
The increase was driven by a larger quantity, but unit values also rose, up 6.5% on March 2018.
While the value of cheese exports rose $42million, butter exports fell, also by $42million.
Other main contributors to the rise in total exports were meat and edible offal, food preparations such as infant formula, forestry products, and fruit, he said.
The decline in imports was due to a 20% slide in purchases of petroleum and products to $516million.
Vehicles, parts and accessory imports were down 11% at $717million while aircraft and parts imports were down 54% at $71million.
- Additional reporting: BusinessDesk.
