The Queensland sugar industry had been headed for a record 39 million tonne sugarcane crop, general manager Ian Ballantyne said in a statement.

He gave no figures on the size of the expected crop after the damage.

The industry, which usually experiences fine and sunny weather at the present time of year, had been hit by torrential wet season type rain, he said.

"The unseasonal deluge has caused severe damage to cane fields from Mackay North and could cost the sugar industry tens of millions of dollars in lost production and additional costs," he said.

There was a strong likelihood that significant areas of cane would now be left unharvested, that total sugar production would be reduced, that some fields would need to be replanted and that millswould have to cope with increased extraneous matter in the cane being processed, he said.

"Torrential wet season type rain has caused untold damage to the current crop at the peak of the harvesting period," he said.

The gains of a few good crop years had been wiped out by the unseasonal downpour and many growers would take years to recover, he said.

"Most of the remaining mature crop has been knocked to the ground by the heavy rain and gale-force winds and some recently planted fields have been washed out," he said.

The most serious effect was that sugar content in cane (CCS), already at historically low levels in many districts, would fall even further, he said.

Growers in the far North of the state would be hit hardest because CCS in districts such as Babinda, Innisfail and Cairns had already been at the margin of economic viability before the latest rain, he said.

The rain would also reduce the productivity of next year's crop, he said.

The setback came at a time when growers had already beenwarned to expect much lower returns from next year onwards, he said.

The world sugar price was at a seven year low and crop returns for 1999 and beyond were uncertain even if the value of the Australian dollar remained low, he said.

The Babinda area had recorded falls of up to 500 mm, or 20 inches, in the past 24 hours. In the Mackay-Proserpine region, some parts had recorded their highest August rainfall in more than 40 years with falls of more than 300 mm, or 12 inches, in 24 hours, he said.

Harvesting in parts of the highly productive Burdekin may have been delayed by up to two weeks, especially in areas already affected by canegrubs, he said. Heavy rain in the Herbert district, based on Ingham, followed damaging floods in January this year. Lighter falls around Bundaberg, Childers and Maryborough had been welcomed by drought-stricken growers but the benefit to crops in that region was more than outweighed by extensive damage in the northern half of the state, he said.

Widespread adoption of greencane harvesting and trash planting from Mackay North had prevented extensive soil erosion, he said.