Apples lead NZ export commodities

World prices for a basket of New Zealand's export commodities posted their strongest rise for two years last month.

ANZ's world commodity price index rose 2.3 per cent on top of a 1.6 per cent rise in April.

April's rise had followed a string of monthly declines, however, and even after the most recent increase world prices are still 2.8 per cent down on a year ago.

The month's increase was driven by a 20 per cent increase in the horticultural export prices as new season Braeburn apples hit the European market.

ANZ economist Steve Edwards said excluding apples, the increase in the rest of the commodity basket was a more modest 0.3 per cent.

"However, the price rises were broad-based with 10 of the 13 recording firmer prices."

The only group to fall was dairy products, down 3.5 per cent.

When converted into New Zealand dollars, the index rise was 1.6 per cent, reflecting a recovery in the exchange rate with the US dollar last month.

Edwards said aluminium prices rose 9 per cent last month, topping US$3000 a tonne as traders speculated on a growing Chinese appetite for base metals.