The devastating impact of the drought in NSW grain-growing regions has been likened to "Armageddon" as a new report says the double-barrel hit from low rainfall and high temperatures in spring have slashed forecasts for Australia's 2019 winter crops.

The latest report to be released on Tuesday by the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) predicts total winter crop production to fall for the third year in a row. The forecast is down a hefty 13 per cent since September due to deteriorating conditions, mainly in NSW and Western Australia.

ABARES is predicting a total winter crop, including wheat, of 29.4 million tonnes, about 27 per cent below the 10-year average.

While NSW grain production has been devastated by drought, it is a different story in Victoria. ABARES forecasts Victoria's total winter crop to be up 92 per cent this year, from a low level, to about 7.2 million tonnes. Victoria's wheat crop is tipped to rise 85 per cent to 3.6 million tonnes.