CHINESE imports of wheat is one of the factors which will hold prices up well into 2013, according to National Australia Bank.

NAB agribusiness general manager Khan Horne said Chinese wheat imports in September were 196 per cent more than they were 12 months ago, due to domestic production concerns.

"On top of that, droughts across the northern hemisphere have decimated crops through the United States, large chunks of Europe and the Black Sea, resulting in a sizeable shift in prices," Mr Horne said.

Chicago Board of Trade wheat futures prices increased slightly overnight to end at 866 US cents a bushel, or $A308 a tonne.

CBOT wheat prices are nearly 40 per cent higher than they were 12 months ago.

NAB said the impact of the northern hemisphere droughts was reflected in Australian feed grain prices, with the NAB weighted feed grains price rising 4.7 per cent in September, to be almost 20 per cent higher over the year.

At $285.30/t, the NAB feed grains price was at its highest level since October, 2008.

NAB is estimating the size of the new season Australian wheat crop at 20.6 million tonnes, in line with other forecasts.

It said the crop was 30 per cent less than last year's record, but slightly above the 10-year average of 21.1 million tonnes.