Twitter has defended allowing users to post messages anonymously.
Enabling people to use the service without giving their real name gave them a "voice" in parts of the world where governments might clamp down on free speech, it told a Dail committee investigating cyber-bullying.
The social media giant's director of public policy for Europe, Sinead McSweeney, said cyber-bullies were suspended from the service, adding it was "acutely conscious" of its responsibility to tackle abusive messages.
"There are Twitter rules. There are limitations on the content which is permitted on the platform," Ms McSweeney said.
"If there is persistent and abusive behaviour, Twitter rules mean that a user can be suspended from the platform and that does happen. Whether a tweet is anonymous or not, they must still conform to our rules. They will be suspended if they violate our rules."
Ms McSweeney was addressing the Dail Transport and Communications committee, which is debating the challenges facing society arising from social-media websites, including Twitter, Facebook, LinkedIn and Instagram.
Some 52pc of the population aged 15 years or older have a Facebook account, while 23pc use Twitter. Ms McSweeney said she was unable to provide information on the number of users blocked from using the site, as users blocked and unblocked followers "all the time".
However, she said anonymity gave people living under oppressive regimes a voice which they might not otherwise have.
"There's a flip side to the anonymity debate," she said. "We see anonymity as giving people who otherwise wouldn't have a voice the opportunity to be part of a world which isn't generally open to them.
"As a concept based on freedom of expression, we see anonymity as being valuable in terms of dissidents or journalists working in conflict zones."
She added that it was important that parents instilled values into their children surrounding use of the platform, as they would not be allowed make "offensive" comments in other situations.
But Timmy Dooley (FF) said bullying was a "feature of life".
"I am somewhat amused at the level of attention that has been given to the level of bullying on any of the social media, because bullying has always been a feature of life," he said.
"You only have to go back to our own school days and we know how people are bullied."
Another TD, Mary Mitchell O'Connor (FG), said parents should sign an acceptance form before their children set up an account.