Other petroleum products more than halved to $23 million from the same month a year earlier. Machinery and equipment exports dropped 31 per cent to $138 million in August.
Milk powder, butter and cheese, and casein and caseinates account for some $12.81 billion in annual exports, or 27 per cent of all of New Zealand's merchandise exports. The volume of milk powder, butter and cheese fell a seasonally adjusted 16 percent to 264,000 tonnes.
That comes as diary exporter Fonterra Cooperative Group today said it missed its forecast payout to farmers due to weaker milk prices and a stronger New Zealand dollar.
The Auckland-based company will make a payout of $6.40 for a full shared-up farmer made up of a farmgate milk price of $6.08 per kilogram of milk solids and a dividend of 32 cents a share. The farmgate milk price was $7.60 a kilogram a year earlier.
The currency recently traded at 81.90 US cents from 82.03 cents immediately before Fonterra's result.
New Zealand's imports slipped 0.4 per cent to $4.1 billion last month, with China still the biggest supplier at $692 million.
ASB economist Jane Turner said the recovery in imports and weaker commodity prices has eroded the national trade surplus which will continue for the rest of the year.
"As a result of the US drought we now see scope for recovery in NZ export prices for meat and dairy over 2013," Turner said. "This should result in the trade balance stabilising and potentially moving back into a small surplus in 2013 (depending on the performance of other export areas)."