Businessman Declan Ganley has received an apology and reached an out-of-court settlement after defamatory comments were made about him on the social media site, Twitter.

Blogger Kevin Barrington said on his blog: "I wish to unreservedly apologize to Declan Ganley for my tweets of 12th December 2012.

"To reflect my regret I have made a substantial donation to the Poor Clare's [sic]".

Mr Ganley's solicitor said that that social media networks are to the fore in what he called the "new battle ground for defamation."

Speaking to RTÉ News, Paul Tweed said the last three months has seen a surge in clients contacting his firm with concerns about defamatory tweets or harassment via Twitter.

Mr Tweed said that while he believed Mr Ganley's legal settlement was the first of its kind, it was a "sign of our times and of a changing media environment."

He said that Mr Tweed said that up until Lord McAlpine's actions against a number of high profile people who had tweeted about him in connection with incorrect allegations emerging from a BBC current affairs programme, many people had not realised that posting a tweet equates to publishing information.

"Once somebody makes a statement, and publishes it online or on their twitter account, that is just the same as if that statement has been published in a newspaper and the same accountability attaches to that," Mr Tweed said.

"It is subject to our defamation laws and the person who posts it will be accountable and will be subject to action under those laws." he added.

Mr Tweed also warned that internet platforms, and not just individuals, needed to be cautious.

He said that because platforms, such as Facebook and Google, operate European headquarters in Dublin, these companies are now subject to Irish and European laws.

This, he said, was a very different environment to that in the US where such companies were protected by the First Amendment.

Earlier, Andrea Martin, of Media Lawyer Solicitors, told RTÉ’s News at One that solicitors are seeing an increase in such cases, but most brought in Ireland have been settled, once the offensive material was taken down.

"Usually in more high-profile cases, where the individual being defamed is high-profile, and or the person who tweeted or blogged is high-profile, that's when you are more likely to see legal cases ensuing," she said.

She said that since the 2009 Defamation Act came in it has been beyond doubt that the law for offline publications applies directly to online publications also.

Ms Martin said: "An awful lot of people look on Twitter and tweets as a conversation rather than as a publication, this case is a stark reminder that the laws of defamation apply directly to tweets and other online publications."