SimSimi, an anonymous chat app linked to cyberbullying, has temporarily removed access to users in the Republic.
The move follows a wave of criticism from students, parents and education authorities.
Schools have been sending letters or text messages to parents in recent days asking them to discuss use of the SimSimi app with their children.
The app – which has been the most downloaded app in the State – allows users to view anonymous, and often insulting, messages left about them by typing in their name.
This afternoon, users were greeted with a message stating: "I do not talk in Ireland for a while."
Many students have taken to Twitter and other social media networks to criticise internet firms for allowing the app to be downloaded and to warn others about downloading it.
The South Korean company that developed SimSimi did not respond to requests for comment on Sunday.
The app works by using a combination of artificial intelligence and used-generated content.
When a user sends a message on their phone, the app responds by scanning for related conversations in its database and responds by spitting out a relevant response.
Ironically, the app was first marketed as a “fun, playful robot”, though much of the content now appears to be vulgar or obscene.
The popularity of the app comes at a time of rising concern over the impact of cyberbullying on young people.
Some 14 per cent of primary school children and 10 per cent of secondary school children have been cyberbullied, according to research conducted by Dublin City University’s national anti-bullying centre.
The centre has advised parents to familiarise themselves with apps and social media spaces used by their children to help prevent cyberbullying.
Harry McCann, a secondary school student and founder of the Digital Youth Council, said the app had been causing alarm among many students.
“It seems to have the sole purpose of insulting and demoralising people,” the 18-year-old said. “We’re planning to raise this at the Government’s data protection forum soon to see what can be done from a safety perspective.”