A dry August has slowed the rebound in Australian crop yields, say official statisticians, who have cut by 2m tonnes their estimate of winter crop production.

The Australian Bureau of Agricultural and Resource Economics forecast at 35m tonnes 2008-09 production from winter crops, which comprise wheat, barley, oats, canola, lupins, field peas and chickpeas. The 5.4% reduction from last month's estimate reflected a "particularly dry" August, the bureau said.

"The lack of winter rainfall mean crops in many areas were suffering moisture stress as they headed into the critical spring growth phase," Abare said, adding that further rainfall was "critical" for production to meet even the revised forecast.

Wheat, the biggest winter crop, bore the brunt of the downgrade, with the forthcoming harvest set to yield 22.5m tonnes, 1.2m tonnes less than Abare predicted last month. The reduction puts the bureau in line with the US Department of Agriculture, which on September 12 cut to 22m tonnes, from 25m, its forecast for Australia's 2008-09 wheat crop.

Nonetheless, Australia's farmers were on course for far fuller hoppers than last year, when a second harvest in a row was blighted by drought.

The latest forecasts imply production increases of 32% in barley, 55% in canola and 72% in wheat. Wheat exports would be, at 15.7m tonnes, more than double those in the current marketing year, which ends this month.

Abare also forecast an 18% decline in production of summer crops which, with a total harvest of 3m tonnes, are a smaller concern for most farmers. The drop was blamed on a reduction in sorghum planting and a lack of water to irrigate rice.