Think you spend less time online than your Facebook-obsessed teen? Think again.

You may see their noses stuck to their phones all day but data compiled by the Australian Communications and Media Authority (ACMA) shows teens are not as bad as adults when it comes to net usage.

Teenagers spend an average of 14 hours and 42 minutes online over a month, research from the communications watchdog says.

That's compared to the 40 hours and 21 minutes spent online by those aged between 18 and 54, and the 32 hours and 12 minutes online by over-55s.

The report found YouTube takes up more time of Australian teenagers online than any other site or application.

Teenagers aged 14-17 years spent an average three hours and four minutes on YouTube, ahead of Facebook's two hours and twenty seven minutes.

Skype took up two hours and twenty five minutes, Tumblr one hour and thirty five, and Microsoft services one hour and twenty five minutes.

Tumblr had the youngest profile of users, with 8 per cent of its users on all devices' browsers (not apps) aged 14-17. Twitter and Pinterest both had only 3 per cent teenage use.

But the data found that such sites are not dominated by teens as widely thought.

Only five per cent of Australians using YouTube via a browser were found to be aged 14-17, with 95 per cent over 18.

The Australian Communications and Media Authority says its research, conducted over December 2013, shows there's been a significant change in the last four years on how teenagers use the web.

More are accessing the net through their mobile phones and they're generally looking for some entertainment, blogging life's musings or even doing some banking and finance.

The report also found a drop in the use of the king of social networks, Facebook, amongst Australian teens.

Fewer are accessing Facebook than they did a year ago. While 70 per cent were using Facebook in 2012, only 58 per cent reported using it in 2013, according to Nielsen.

ACMA says one thing's certain: as children age, the internet becomes an increasingly integral part of their lives, whether it's for social interaction or education.