The Press Ombudsman has criticised the reaction on social media to the arrest of a man by gardaí investigating the murder of Tullamore teacher Ashling Murphy.

The man was eliminated from Garda enquiries last night.

Peter Feeney said there were reports that this person had been identified on social media and this highlighted the need for regulation.

"It wasn't journalists who identified the man, it was reckless social media users," he said.

Speaking to RTÉ News, Mr Feeney said that social media is "entirely unregulated" in Ireland.

"While all social media companies have a complaints procedure, it is not fit for purpose.

"Firstly, you cannot just call them up, you have to email them. That email can be picked up anywhere in the world. The response can be a very slow process."

The Press Ombudsman said he welcomed the publication of the new Online Safety and Media Regulation Bill by the Department of Tourism, Culture, Arts, Gaeltacht, Sport and Media.

"What happened in Tullamore has highlighted the need for, and the importance of, this Bill - it is critically important that social media comes under some form of regulation.

"So while I welcome the Bill, it is still very early days and it will be some time before this becomes legislation."

Mr Feeney said the legislation will set out fines that social media companies will have to pay if they refuse to take down material that is harmful, once it has been reported to them.