DRY conditions and low cereal prices have contributed to a 10 per cent fall in the area sown to crop in Western Australia.

Bulk handler and grain marketer CBH Group estimates the state's grain growers have only planted a winter crop of 6.7 million ha, well down from the 7.4 million-hectare average.

CBH operations general manager Colin Tutt said: "It will be 6.7 million hectares if we're lucky".

He said crop plantings in some areas had been reduced by 10-30 per cent.

"I know a lot of growers pulled up 20 per cent short, or 15 per cent short," he said.

Mr Tutt said the south-western region of WA was faring well but "the rest of the state is just struggling".

"This season will be about growers preserving equity in their business," Mr Tutt said.

"It will be a very, very light crop.

"Growers have been very conservative about how much they have planted."

Mr Tutt said low cereal prices, a lack of subsoil moisture and a dry outlook all contributed to lower plantings.

CBH was expecting the Western Australia winter crop production at 8-11 million tonnes.

That was well below the Australian Bureau of Agricultural and Resource Economics' estimate in its crop report released two weeks ago.

ABARE has forecast a 12 million-tonne crop, well above its 14-year average of 11.9 million tonnes.

The bureau also estimated plantings at 7.5 million hectares, about 100,000ha above the average sized crop sown since 1997.

Former WAFarmers grain section president Derek Clauson said he had cut his farm's cropping area by 200-240ha this season.

Normally, Mr Clauson planted a 2000ha crop on his farm at Beacon, 250km north-east of Perth.

He said his farm had the lowest subsoil moisture on record after a string of dry seasons and no summer rain this year.

"Some parts of the farm haven't had two inches (50mm) of rain for the year," he said.

"We will need good rains through the season just to get an average crop."

Mr Clauson said most of the state's farmers had completed sowing.

"If anyone is doing any more sowing, it is for soil conservation purposes on the sand plains to stop it blowing," he said.