300 children who had planned suicide called Childline last year
More than 300 children who called Childline last year had already acted on or made plans to take their own lives.
The helpline received 652,383 calls and was able to answer 462,505 of them, or some 1,200 a day.
The charity's online service, which provides support via a one-on-one live chat service on the web, recorded 17,820 contacts last year.
"One of the main concerns that we have about last year's information is that we had 1,000 calls from children who were suicidal, and of those, 300 had acted on their suicidal thoughts," said Childline's director of services, Caroline O'Sullivan.
Gabrielle Geraghty, who has volunteered with Childline for six years, said she recently spoke to a teenage girl who had tried to take her own life.
"Just last week I had a call from a 17-year-old girl and she had attempted suicide three weeks before," she told the Herald.
"She had taken an overdose, a concoction of alcohol that was in the house, because she was so upset about her parents splitting up.
"The parents were using the children as pawns and she couldn't see any other way out than to take her own life, and that's just so sad because as adults we need to be aware that children do need to talk.
"It is difficult to hear those things, but to be there at the other end of the phone and to be able to listen to them is a huge part of what we do."
The latest figures were released yesterday at the launch of the ISPCC Childline Report for 2014.
Speaking at the event, ISPCC chief executive Grainne Long said children's mental health remained a key feature of calls to the charity.
More than 22,000 calls last year related to mental health, and issues ranged from bereavement to anxiety and thoughts of suicide.
Nearly 30,000 contacts were made in relation to sexuality, with children wanting to talk to someone about their own sexuality, contraception, sexual behaviour and sexual health.
Childline also saw an increased number of calls in relation to gender identity and sexual orientation.
During the launch, a number of Childline ambassadors were honoured for raising awareness and helping with last year's emergency appeal.
These included Ryan Tubridy, senator Jillian Van Turnhout and actress Saoirse Ronan.