There are claims that Western Australian grain farmers are warehousing this year's harvest because of uncertainty over whether the troubled exporter AWB will maintain its monopoly.
While many farmers have already harvested this year's crop, it is still not clear who will be selling their grain on the world market.
The chairman of the Western Grain Growers, Leon Bradley, believes most farmers are storing their wheat rather than selling it to AWB.
He says they are waiting to hear if WA-based rival CBH is successful in its bid to secure an export licence.
"It's been up to 80 per cent in some regions and around about 70 per cent in others, so it's very significant because normally you would expect 80 per cent of the wheat to be assigned to AWB upon delivery," he said.
AWB has twice used its veto powers to reject CBH's attempt to export 2 million tonnes of wheat.