WELLINGTON: Prices for New Zealand's main commodities edged up in August, rising for the second consecutive month due to gains in prices for aluminium and skim milk powder, the ANZ Bank's commodity price index showed on Tuesday.

The index rose 0.7 percent from July, taking the annual rise to 26 percent. The index is 5.3 percent below a record high touched in April.

Prices for whole milk powder, beef, cheese and casein also rose, along with apples and sawn timber, offsetting a slide in prices for butter and pelts.

In New Zealand dollar terms, the index also rose 0.7 percent for the month as the domestic currency weakened slightly. It was 6.2 percent off its record level hit in March 2011.

ANZ's index includes commodities which make up around 60 percent of the agricultural economy's NZ$46 billion ($35.95 billion) annual export earnings.