In a statement to the Australian Stock Exchange on Friday, PrimeAg executive chairman Peter Corish said the timing of the rainfall was disappointing as it had resulted in damage to the winter crop, which in turn would impact on the company's financial performance for 2008/9.

Mr Corish said that harvest was now 67pc complete, but only 45pc was harvested prior to the November rains.

"The portion of the crop harvested pre-rain was in line with yield and quality expectations, however as the harvesters have returned to the field, we are seeing evidence of yield loss and quality downgrade on the unharvested portion," he said.

Mr Corish said that a full assessment of the winter crop losses could not be quantified until the harvest was completed, and about two weeks of clear weather was required to achieve this.

However, he said it was clear that the reduction in winter crop revenue, from both yield and quality shortfalls, was likely to be material, and preliminary indications were in the range of 10–20pc.

ABARE today reported that the final size of the national winter crop would be about 31 million tonnes, a 36pc increase from 2007/08, but well down on mid-year expectations.

"Australian wheat production is estimated at around 20mt in 2008/09, largely unchanged from ABARE's October 2008 forecast, but well down on mid-year expectations," ABARE executive director Phillip Glyde said.

"The poor spring also hampered the potential of barley and canola crops."

However, Mr Corish said the November rains would set up the company's properties for bumper summer crops.

"Consistent with our strategy of varying the crop mix as conditions dictate, areas of sorghum, maize and other crops will be planted to utilize the additional irrigation water that has become available as a result of the recent rains," Mr Corish said.

"The 2500ha irrigated cotton which has been planted on various PrimeAg hubs now has ample irrigation water to take this crop to completion, however the timing of the rains does not allow additional cotton to be planted.

"Importantly, the rains allow completion of the planned 5000ha dryland sorghum crop and 500ha of dryland cotton crop."