Exports of milk powder, butter and cheese reached record high in December 2011, leading to a trade surplus.

The trade balance was a surplus of $338 million in the month of December, Statistics New Zealand said. In contrast, the median forecast was a $100 million deficit in a survey by Reuters.

The forecast had been based to a deficit of $307 million in November, which was originally reported as a deficit of $308 million.

The value of exports rose 13 per cent to $4.3 billion in December from the same month in 2010, while imports fell 1.6 per cent to $4 billion.

"Milk powder, butter and cheese exports reached a record high in December 2011, up $329 million to $1.4 billion... This increase was led by exports of unsweetened whole milk powder, which also reached a new high, up $171 million, or 37 percent, with quantities up 30 percent," Statistic New Zealand said.

There was a trade surplus of $698 million in the December quarter, and the annual trade balance was a surplus of $1.1 billion.

Exports to Australia went up 30 per cent, but imports from the US decreased 39 per cent, and the difference could be attributed to the importing of a large aircraft in December 2010.