Despite the overall Westpac-NFF Commodity Index falling only 1.3pc over October, this masks volatile price movements – from falls of 9.2pc to gains of 7.6pc in different commodities.

While grain and wool prices decreased by 9.2pc and 8pc respectively at the bottom of the scale, these were partially offset by substantial price rises for dairy of 7.6pc, sugar 4.1pc, and beef 3.3pc.

"The weakening Australian dollar prevented what could have otherwise been an extreme month for global agricultural commodity prices," Westpac senior agribusiness economist Andrew Hanlan said.

"Pricing fundamentals do not always prevail when erratic market conditions, such as those currently being experienced on world financial markets, start to dominate investor decisions.

"This can definitely be said of this month's agricultural commodity price movements and reinforces the variability that can be an aspect of all commodity markets when investor confidence receives a shock."

NFF vice president Charles Burke says the fluctuating fortunes that beset Australian farmer's prospects are highlighted by the 2008 winter crop harvest, which is "looking to be a real mixed bag".

"As the winter grain harvest kicks off across the grain belt, farmers in much of northern NSW, Queensland and WA are looking at solid yields," Mr Burke said.

"However, a lack of spring rainfall across southern NSW, Victoria and SA has seen a noticeable deterioration in the winter crop forecast in those regions, with ABARE downgrading their winter wheat production forecast to less than 20 million tonnes.

"With these uncertain weather patterns continuing to beset agricultural production in Australia there will be winners and losers this winter."