AUSTRALIA could become a "Third World wine producer", with the prospect of losing all the huge gains made since the 1980s, the nation's leading wine commentator warns.

Winemaker, author, critic and wine show judge James Halliday issues the warning in his latest Australian Wine Companion 2010, launched today.

In the book Mr Halliday writes that the global recession, wine glut, exchange rate fluctuations, drought and the prospect of climate change is making the "future of the Murray Darling almost impossible to predict".

"Out of these and other issues, the view has emerged that the annual crush should be permanently reduced by up to 400,000 tonnes ... so 46,500ha have to be removed" he writes.

However, he said if the annual crush was cut while record low inflows into the Murray Darling became permanent, the worst case scenario would emerge.

"We (would) have removed 45,000ha from cool regions and suddenly find the Murray Darling's capacity has been permanently crippled.

"In this nightmare scenario all of the massive gains the industry has made since 1985 will evaporate, and - in wine terms - we would be a Third World producer."

Speaking to The Weekly Times this week at his Yarra Valley home, Mr Halliday said while he was unconvinced about the science of climate change, the continuing drought did not bode well.

"We have always lived in a water-starved country, but if the changes in the weather patterns which we've been experiencing at the moment become normal, then we will seriously have to consider making wine in the northern part of the country.

"The current position of the Murray Darling is horrible. At best we are treading water in terms of water rights. Future allocations will go to cities and to keep livestock alive.

"Whether it's positive planning or a steady erosion of water security, we will see a lot less wine produced."

Mr Halliday said despite this scenario he was optimistic about the industry's future, particularly on the back of the growing Asian markets.

"In the medium term I am an optimist," he said.

"You can't overlook the fact that between 1995 to 2000 Australia came from absolutely nowhere to become the fourth largest exporter in the world.

"We have had an extraordinary period of success, which you don't have unless you have a really good product with commitment behind it."