An Oireachtas Committee has heard that getting people to pay to post on social media websites or register their passport numbers for IP addresses could help tackle the issue of anonymity of the internet.

Senator Eamon Coghlan made the suggestions as the committee examined the link between social media and cyber bullying.

He raised the issue of anonymous posts, and had a number of suggestions for tackling the issue, including paying to post and registering your passport number:

Speaking at the same Committee, the Communications Minister Pat Rabbitte said he has difficulties with the take-down policies of companies like Facebook.

Mr Rabbitte said: "These are reputable companies (and ) major corporations. Good corporate citizenship should mean, it seems to me, that they should be prepared in the host country to enter into sensible protocols about take-down policy."

The Oireachtas Communications Committee is embarking on a series of meetings with companies, like Facebook and Twitter, to examine the links between social media and cyber bullying.

Communications Minister Pat Rabbitte told the Committee that his department is examining any gaps in legislation when it comes to posting defamatory material online.

He also raised concerns about the policies used by social media companies when it comes to taking down offensive posts.

Senator Fidelma Healy Eames raised the issue of when someone's Facebook account is changed by someone else, and said teenagers are literally living in a parallel universe.

She said: "Where a youngster has their status opened and another person puts a message on there, as if they wrote it, and that message could be, for example sexual. This type of thing has to stop.

"There has to be some controls put here. What about sexting, where they are texting sexual images?"

The Committee will continue its hearings on the issue for a number of days before making a series of recommendations.