For 19-year-old Kate Crowley and her girlfriends, a few sips of a Bacardi Breezer or two used to be vital preparation for a night out in Brisbane's Fortitude Valley.

Not anymore.

Ms Crowley admitted kicking off last Saturday night with something much stronger.

"We decided to mix our own drinks from a bottle of Absolut Vodka, purely because it worked out cheaper," Ms Crowley told brisbanetimes.com.au.

Following last month's tax hike on ready-to-drink (RTD) alcohol products, also known as alcopops, Ms Crowley's choice reflects a growing preference for do-it-yourself mixing among alcohol consumers.

While national alcopop sales plummeted by almost 40 per cent in the fortnight after the Rudd Government lifted the excise on the drinks, liquor stores across Brisbane have reported a 20 per cent jump in stronger, straight spirit sales.

"Why would we spend more money on pre-mixed drinks, when we can buy better and more alcohol for the same price?" Ms Crowley said.

The first national data on alcohol sales released today by the Distilled Spirits Industry Council of Australia (DSICA) confirmed consumer logic had all but nullified the government's bid to curb binge drinking by young people by raising the tax.

"This new data is the first, hard and unequivocal evidence of the unintended social and health consequences of the government's RTD tax hike," DSICA information and research manager Stephen Riden said.

"Not only have consumers simply substituted full strength spirits for RTDs, the real problem is that self-mixing drinks makes it near impossible to know how much alcohol is being served and consumed.

"While people pour what they think is an average drink they are, in fact, mixing a much stronger one," he said.

For the manager of one West End, liquor retailer, who asked not to be named, the health consequences for young people far outweighed any possible boost to the business' bottom line from increased sales of straight spirits.

"There's no sense in looking at this from a business point of view...I've got great concerns for the young people who are mixing their own drinks irresponsibly," the manager said.

"We have recorded a great drop in sales of pre-mixed drinks, yes, but that has been clearly counteracted by more sales in straight vodka and rum."

The Federal Govenment insists figures showing the sale of spirits had dropped by one million standard drinks acrioss the country was proof its tax measure was discouraging binge drinking.

"What it actually equates to by the industry's own admission is an overall decline, when you look at the decrease and the increase ... of one million standard drinks of spirits less that have been sold in a two-week period," Health Minister Nicola Roxon told parliament yesterday.

"We have the industry with a clear self-interest aligned with the opposition and we have every other health expert in the country aligned with the government."

Despite concerns, Ms Crowley said she and her friends made a conscious effort to limit the amount of full strength alcohol they drank.

"Then again, it would take me 15 minutes to drink a Bacardi Breezer and only five seconds to take a shot of vodka...and I'd want another shot a lot sooner too," she said.