Facebook has a minimum age restriction of 13 years and Twitter technically requires users to be over 18, but many tweens – children aged between 10 and 13 – are still accessing these and other social networks, according to a study by security providers AVG.

For the fourth and final part of the company's Digital Diaries study, Digital Maturity, researchers asked parents around the world, including 800 in New Zealand and Australia, about their tweens' social network habits.

58% of parents admit their tweens have access to mainstream social networks. For 10-year-olds the figure is 37%, while by the time they reach 13 it is over 75%. 47% of children at this age are also accessing the sites via their mobile phones.

12% of New Zealand 13-year-olds spend over 11 hours per week on social networks.

Most sites follow Facebook's lead of setting a 13-year age restriction. Twitter doesn't take a user's age, but as part of its terms of service users must be able to form a binding contract, and to do this they must be 18 (unless their parent or guardian does so on their behalf).

Michael McKinnon, the security advisor for AVG ANZ, says many children match or exceed their parents' technological abilities by their tween years.

"However, they have not developed the equivalent intellectual or emotional maturity necessary to make the right decisions in the many complex situations they face online,” McKinnon says.

"It is important that parents understand the role technology plays in their children's lives to help their kids be as smart and safe as possible whenever they are connected.

40% of New Zealand tweens have their own PCs and 44% of those use them in their bedrooms, where it is harder for parents to monitor their behaviour. 61% of kiwi parents have used their kids' computers to monitor their activities, and 48% have logged into their social media profiles.

59% of parents know their kids' passwords. Mums are more likely to check up their kids than Dads.

"Adults often take for granted the decades of daily, hourly, minute-by-minute training we call upon every time we engage with other people,” McKinnon says.

"And not even we can navigate social situations without having to reconcile a host of complex issues, from simple etiquette to gross invasions of privacy, sexual inappropriateness and social bias.

The others studies performed as part of the Digital Diaries campaign were Digital Birth, Digital Skills and Digital Playground.

Do you think tweens should be accessing social networks?