Irish teenagers spend an average of 43 minutes per day on the social networking site Bebo, 10 minutes more than their British counterparts, according to figures supplied by the company.
A seminar for parents in Dublin yesterday also heard that while new generations of social networking sites are targeting the pre-teen market, the issue of age verification remains a challenge.
The Government-sponsored Make IT Secure seminar also heard concerns about the prevalence of advertising aimed at young people using such profit-driven sites, and the use of the sites by employers and others to do "background checks" on potential employees.
John Carr, an adviser to the British government on internet safety, said the positive side of the internet "massively outweighs" the downside.
"At the same time, we have to acknowledge the dangers," he told those present. "We haven't found the right way to help parents to understand the technology."
Mr Carr said he was aware of situations where children were going online and pretending they were older than they were, in turn allowing them to order pornography and alcohol online.
While he was confident that the introduction of age verification was "inevitable", he noted that children would be unlikely to use a site that their "priest and mother" wholly approved of.
He also expressed concern about the recent case of a Cambridge admissions tutor who acknowledged researching the backgrounds of prospective students via such sites.
Yesterday's forum also heard concerns about the type of advertising to which children are exposed on social networking sites. Anne Conroy, who works for Barnardos, said she had accessed advertisements for sites for Russian brides, alcohol sales and online drugs stores via Bebo.
According to Dr Rachel O'Connell, Bebo's chief safety officer, any advertisements on its site are age appropriate.
However, she acknowledged this was based on the age supplied by a user, which currently could not be verified.
Separately, figures supplied by the company yesterday suggest that 686,000 Irish people aged 15 or over have their own profile on Bebo, with users spending an average of 43 minutes a day using the site.
Fewer than 600 of these are aged over 18.
This compares with an average of 33 minutes' usage a day in Britain.
When 13- and 14-year-olds are included, Bebo claims to have more than one million Irish users. Users have an average of 17 online "friends".
Pat Edmondson, a mother of two girls from Booterstown, Co Dublin, said it was important to bear in mind that sites targeted at pre-teens were also very popular, with new sites coming on stream often.
"A lot of parents don't understand the technology," she said. "I think it is absolutely impossible for anyone to keep up to speed with the changes in the internet."