Australian researchers say alcohol brands are using Twitter to promote their products to a young and potentially underage audience.

A research team from the University of Western Sydney tracked the tweets of various global alcohol brands - including Corona, Heineken, Smirnoff and Jack Daniels - for six months.

It found their initial tweets were often re-tweeted to a much larger audience which increased the risk of them being seen by users aged under 18.

It also found the use of hashtags increased the audience by attaching the alcohol promotions to popular social events such as concerts.

The study is published in the latest Medical Journal of Australia.

Co-author Dr Ann Dadich says there should be tougher regulations in place for alcohol promotion.

"There's quite a large young demographic that is using Twitter, a number of people may be thinking, 'well it's too difficult to manage this'," she said.

"Twitter is a relatively new platform for companies, and what we found is that it seems to be quite an efficient way to promote their wares.

"In addition to their direct audience, they're obviously getting that secondary audience as well."

The report highlighted Budweiser's Twitter activity.

During the aforementioned six-month study period, the company sent 286 tweets to its 15,000-plus followers.

The tweets were subsequently retweeted 13,523 times.