Melbourne, May 9 : According to a survey, cyber bullying is affecting more than one in five young Aussies.

The poll found that the Internet plays a critical role in the lives of 15 to 20-year-olds, with 64 per cent having a social network site such as MySpace or Facebook.

But, according to the annual Youth Poll survey released by Senator Natasha Stott Despoja, 22 per cent had been harassed or bullied online.

The national poll found rates of youth binge drinking, smoking and other drug use were declining compared with other years, reports News.com.au.

Body image was a major concern to 54 per cent of the youths surveyed, 46 per cent of whom knew someone who had committed suicide or tried to do so.