Just over 20 per cent of Australian parents suspect their kids of sexting, and 41 per cent are accessing their Facebook accounts without their consent, a survey of 11 countries by the company AVG found.

Some children, however, have been turning the tables with fake updates about themselves, University of Canberra law lecturer Bruce Arnold has said.

''There is anecdotal evidence that kids are swapping their phones with friends so the geodata says they are in a different place when they update their profile,'' he said.

''Location technology is not very sophisticated, you can give your smartphone to your little brother and ask him to manage your Facebook account for a few hours for you.''

Australian technology analyst firm Telsyte senior research manager Sam Yip said kids could be caught out by being tagged in their friends' photos with Facebook's facial recognition software.

''You can track your kid through their friends' pages and if somebody makes a comment on a photo it can go up on the friend's wall so everybody sees it,'' he said.

''If that's a picture at a party they weren't meant to be at - the secret is out.

''It's not just about locking one or two things, you have to lock about 30 features across several devices to keep a determined parent out. The majority will slip up.''

The AVG data found in its study Digital Coming of Age, the fifth instalment of AVG's digital diaries series, that 42 per cent of Australian parents were worried that their teen's interaction with social media sites could affect their future job prospects. Parents were also worried that their children were illegally downloading music.

But the research also found that Australians were generally more trusting of their children than parents in other nations.

Of parents in the United States, 61 per cent secretly accessed their teen's Facebook account, compared to another 61 per cent in Spain and 54 per cent in both Italy and Canada.

Mr Arnold said parents should hesitate before leaping in however, because the relationship with their child was on the line.

''The technology is ultimately neutral, you can use it or misuse it,'' he said.

''In terms of whether you should or shouldn't do these things the argument has been 'just because you can do something doesn't mean you should'.

''Is there a reasonable justification? Is your kid in real danger? There is a difference between looking through a five-year-old's diary and a 15-year-old's diary''.

Mr Arnold said some technology had been marketed to husbands and wives who suspected their spouses of having affairs, which was just as easily applied to one's offspring.

''There are a number of services where you can effectively 'bug' your kid's phone or their network service so that whenever the child sends what they think is a private SMS or communication to someone else the parent also receives a copy of that message in real time. Some of those services are reasonably sophisticated.

''But there is a lot of research that says kids need some autonomy, kids like risk taking and it's part of growing up. There's an issue of cotton wool kids in Australia and mum and dad not giving them the autonomy to fall over and learn from it.''