Export commodity prices fell in February to their lowest level in almost four years.
The Reserve Bank of Australia's index of commodity prices was 1.3 per cent lower in foreign currency terms in the month.
Coking coal and iron ore were the most important contributors to the monthly fall and were partly offset by a rising gold price, the RBA said on Monday.
The RBA said the prices of many base metals fell, while many rural commodities enjoyed price rises.
The February level of the index was 27 per cent lower than its peak in July 2011.
It was last below the current level 47 months earlier in March 2010.
And there appears to be more falls already in the pipeline.
The decline in commodity prices over the past 12 months was 12 per cent in foreign currency terms, based on prices actually paid, often under contract.
But, the RBA said, using spot prices - those negotiated in real time - the index would have fallen by 17.5 per cent through the year to February.
Between the July 2011 peak and February, the Australian dollar fell by an average of 11 per cent against the currencies of Australia's trading partners, according to RBA data.
That fall in the exchange rate has cushioned the blow but not completely nullified it - the index is still down by 17 per cent from its peak when measured in Australian dollars.
The foreign currency price index is measured in terms of special drawing rights (SDRs), an average of four major currencies - the US dollar, euro, Japanese yen, and British pound.
