Better-than-expected grain receivals and exports are expected to boost the both the full-year and provisional half-year results of the agribusiness group.

In a market update, GrainCorp said the half-year profit was now likely to be $32 million, up to 40pc higher than the $23-$28 million estimate made at the annual meeting in February.

This will push the full-year profit guidance to $37-$42 million.

Managing director Mark Irwin said grain receivals to date were within the market guidance of 9.05 million tonnes.

"We estimate the total receivals will be between 9.2 and 9.4 million tonnes by the end of September," he said.

Mr Irwin said the company had handled more than 2.5 million tonnes of grain through its port terminals so far this year.

"Based on forecast shipping demand ... we have increased our export tonnage forecast throughput to more than 4 million tonnes by the end of this financial year."

However Mr Irwin was cautious on the grain export forecasts.

Exports may be reduced by factors such as the value of the Australian dollar and the size of the northern hemisphere harvest.

"Our export tonnage assumptions are based on forward vessel nominations and bookings, and any significant change to these amy have an impact on the tonnage of exports we handle," he said.

GrainCorp will release its results next Monday.

In afternoon trade, Graincorp's shares were up 45, or 6.5pc, at $7.30.