More than one in five (21 percent) web users are concerned about what their children get up to on social networks such as Facebook, says SpectorSoft.

Research by the firm that makes internet monitoring software revealed that kids stumbling across inappropriate content is a concern for nearly a third (29 percent) if parents, while the likelihood of their child interacting with a sexual predator online comes a close second, with 22 percent of parents admitting to being worried about it.

Furthermore, more than half of parents (51 percent) admit they think their child shares too much information online.

More than a third of web users (37 percent) say their child spend between one and two hours online every day while almost as many claim their child spends between two and four hours online every day. Nearly two thirds (63 percent) said social networks were the type of sites visisted by their children most, while 18 percent named gaming sites and 11 percent said their child uses the web mostly for schoolwork.

The research also revealed 17 percent of parents admitted their child had experienced cyberbullying, while nine percent said they had suspicions their child may have experienced cyberbullying.

Nearly three-quarters (73 percent) of parents surveyed said they talk to their children often or quite often about internet safety.

"Based on the survey data, there is little doubt that parents have their hands full as they seek to protect their children online," said Lisa Shaw, senior director, child safety of SpectorSoft.

"Parents are grappling with the vast amount of inappropriate content that their children can access via the Internet, as well as the threats posed by malicious individuals. Knowledge of their children's online activities is essential for ensuring their safety and teaching them to use the Internet responsibly and safely."

See also: 25% of 8 to 12 year olds have a Facebook profile