Increasing salinity in Australia's biggest wine regions could be a barrier in important export markets, an official report has warned.

The Australian Bureau of Agricultural and Resource Economics said salinity was a problem in the New South Wales, Victoria and South Australia irrigated regions along the banks of the River Murray in the south east of the continent.

More than 20,000ha are used for grape growing and the A$1.5 billion (US$975m) annual production could be affected by saline irrigation river water and rising water tables.

The Bureau warned that a problem could arise in markets with tough restrictions on the amount of sodium chloride in wines. Germany had already barred some Australian wines for this reason. The Bureau said more efficient irrigation and other viticultural measures could minimise the impact.