Nearly 100 children have been waiting for at least 18 months for an appointment with the mental health service.
According to details released under the Freedom of Information Act, more than 50 kids have been on the list for more than two years.
At the end of December, there were 2,327 kids waiting for an appointment with the HSE's Child and Adolescent Mental Health Service (Camhs) - 100 more than last July.
A total of 212 have been waiting for more than a year, with 52 on the list more than two years and seven for more than three years.
The Cork and Kerry region is the worst affected area, with 619 people waiting for an appointment.
Across the two counties, 145 kids have been on the list for more than a year.
Brendan Kelly, a professor of psychiatry in Trinity College Dublin, said the waiting times were a concern.
"Children and adolescents with mental health problems need particularly urgent attention," he said.
"Waiting periods lead to a deterioration in mental health, lost opportunity for education and other activities, so waiting times are very concerning."
The HSE says there are significant efforts on an ongoing basis to reduce waiting times for Camhs, which it says are partly down to recruitment issues.
It says there was a 24% increase in referrals to the service between 2012 and 2018.
