Farmers in eastern Australia are being told to prepare for less rain later this year with early climate models suggesting a return to the El Nino weather pattern.

El Nino events are often accompanied by cooler sea surface temperatures in the western Pacific Ocean.

This results in lower-than-average rainfall over the eastern half of Queensland, and areas south through New South Wales and Victoria.

Climatologist Professor Roger Stone from the University of Southern Queensland in Toowoomba says early modelling from the US and Europe indicates a change from the current neutral weather pattern to an El Nino.

"It's early days yet and we hope it'll turn around and go a different way but the fact that the models are starting to pick something up already is slightly concerning.

"I think it's hard to put a percentage on it yet, there's only two of the models showing it but they're the best models," he said.

Professor Stone says a more accurate prediction will emerge late in autumn.

Professor Stone says El Ninos usually last for a year and farmers need to pay close attention to long-range forecasts.

"If there's potential to go into a drought-type pattern then you'd normally suggest a fairly cautious approach to risk management," he said.