BEER will be short supply, more expensive and may taste different as climate change affects barley production, a scientist says.

Drought conditions in parts of Australia where malting barley was grown was likely to get worse, according to Jim Salinger of New Zealand's National Institute of Water and Atmospheric Research.

Barley production in the main growing region of Canterbury in New Zealand - where brewing giant Lion Nathan gets about 70 per cent of its malted barley - would also be affected, the New Zealand Press Association said.

"It will mean either there will be pubs without beer or the cost of beer will go up," he said.

Malting barley production in Australia was likely to be hit hard in parts of Western Australia, South Australia, Victoria and NSW.

The dry areas of Australia would become drier and water shortages would get worse.

"It will provide a lot of challenges for the brewing industry," Dr Salinger said.

He said breweries could be forced to look at new varieties of malt.

Dr Salinger told the Institute of Brewing and Distilling convention in Auckland today that by 2100, the atmospheric concentration of greenhouse gases - measured in equivalent amounts of carbon dioxide - would be double, and possibly four times pre-industrial levels, leading to further climate warming.

"Most areas in Australia where malting barley is cropped are likely to experience producing declines," he said.