MORE than 200,000 Australians are living with undiagnosed permanent brain damage caused by drinking alcohol.

And a further two million people - one in eight adults - are at serious risk of joining them due to the amounts they consume, health experts warn.

Yet the country is woefully ill-informed about how much alcohol puts a drinker at risk of brain injury.

People tend to vastly overestimate the number of drinks they can consume each day before putting themselves in harm's way, risking damage to memory, concentration, organisational skill and problem-solving ability.

Research to be released today shows 70 per cent of men and 60 per cent of women have no clue about the volume of alcohol required to put them at risk of suffering brain damage.

The Roy Morgan survey shows one in five women believe they can consume four standard drinks a day over eight to 10 years without incurring brain damage, when in fact drinking atthat level puts them at significant risk.

A standard drink is equivalent to one 285ml beer, less than a can, or 100ml of wine, considerably less than the usual glass served at a restaurant or bar.

Disturbingly, 20 per cent of males aged 14 to 17 believe they can drink up to 20 standard drinks a day for eight to 10 years before risking brain damage, when the actual amount is six or more standard drinks. For women, the level is much lower at three or more standard drinks a day over the same period.

The survey was commissioned by not-for-profit alcohol treatment group Arbias, supported by a raft of top agencies including the Mental Health Council of Australia and the Australian Drug Foundation.

Arbias chief executive Sonia Berton said so many people were already affected, and so many more were on their way to alcohol-related brain damage that "a health crisis clearly beckoned".

"Alcohol-related brain injury affects as many as one in eight Australians," Ms Berton said.

"It's slow, progressive and ultimately this damage affects a person's thinking, emotions, communication and ability to care for themselves." She said the damage was not confined to one demographic, affecting young and old, rich and poor, black and white, male and female.

"People need to understand that it's not a question of how much you have to drink to sustain an alcohol-related brain injury, but how little.

"Few Australians realise alcohol-related brain injury exists outside of chronic alcoholism. Many people think you'd have to be drinking several bottles of wine every day or slabs of beer. Nothing could be further from the truth.

"The average wine glass holds far more than 100ml, as much as 200 or 250ml. If we went to a restaurant or pub we would feel ripped off if we were poured a 100ml glass.

"Many women are thinking: 'I'm not drinking near the levels I hear about, I'm just having two glasses of wine at night.' They need to be very aware."

In the past decade the number of Australians drinking at risky/high-risk levels (six or more standard drinks for males, three or more for females) had increased by 60 per cent, according to the National Health Survey.

In 1995 8.2 per cent of Australian adults were drinking at these levels, but that increased to 13.4per cent in 2004-05, the latest available figures.

Clinical neuropsychologist Martin Jackson said many people were unaware they were already suffering brain damage from their alcohol use because they continued to function.

Warning signs were short-term memory loss, anxiety, anger and confusion.

"I am certain there are hundreds of thousands of people out there undiagnosed with this injury," Dr Jackson from the school of psychological science at La Trobe University said.

"People often get brain damage long before they actually get sick. By the time they show up in the health system, unfortunately, they have lost their jobs, families and thinking abilities."

Ms Berton said it was a disgrace that Melbourne was the only city in Australia offering a diagnosis and continuing treatment program for people with alcohol-related brain injuries.