Demand for a pilot programme for online counselling for young people has doubled since its launch last October.
0800 What's Up was solely a phone-counselling service before its online chat sessions were introduced.
It said its counsellors had since been involved in more than 1400 online chats, covering such issues as family violence and mental health.
Spokesperson for 0800 What's Up Mike Munnelly said they underestimated the seriousness of the issues people would chat about online.
"It looks like your people are starting to use that for more serious issues, dealing with situations of abuse and family violence and how to cope with those [and] their own feelings of depression and self worth."
Mr Munnelly said they were planning to make the online chat room permanent and needed more funding.