COTTON farmers are preparing to plant what could be Australia's biggest crop in a decade.

According to Cotton Australia, growers are forecast to plant 323,000 hectares of cotton in NSW and Queensland this year after excellent winter rain and strong cotton prices.

The only detractor would be the potential locust plague.

Cotton Australia chief executive Adam Kay said he expected cotton farmers to produce 2.7 million bales this season, worth $1.35 billion.

"It looks like 232,000 hectares of irrigated cotton will go in, while the big shift is in the number of dryland hectares being sown," Mr Kay said.

"Our estimates show that more than 100,000 hectares of rain-grown cotton will be planted, making this easily the biggest cotton harvest since we emerged from drought."

Cotton prices have reached $500 a bale this season, the highest for a number of years.

NSW cotton grower Peter Booth is preparing to plant 200ha of cotton on his property at Warrawidgee, near Griffith.

Rain, the better seasonal outlook and improving water allocations on the Murrumbidgee River system have prompted him to be more optimistic.

"Price is about 10-15 per cent up this season," he said.

"But the locusts may hit us in mid-November ... and we are sowing in September-October.

"It could be a challenging season."