The sexual violence support group One In Four has warned of the risk of suicide among vulnerable people waiting long times for appointments.

Speaking to RTÉ's This Week programme, the organisation's Executive Director Maeve Lewis said that she was aware of at least four people who had taken their own lives while waiting for an appointment over the past six years.

She said that in each case the organisation only learned that the person had taken their own lives when One In Four sought to contact them offering a belated appointment.

"It's not a unique problem to One In Four. Any of the services working in the field of sexual violence operate with very long waiting lists; and every year for the last four years, we've had to close our waiting list for a number of months because it had got so long, to the point that people would be waiting up to a year to get an appointment," Ms Lewis added.

She said ideally they would like to see people within several weeks. One In Four attempts to fast-track anyone who seems suicidal, after an initial assessment, she said.

However those who do not initially raise a flag may have to wait lengthy periods to be seen.

"The person may be waiting months, maybe six or seven months, before we have an appointment available for them. At the moment, our waiting list is closed again. And it is a constant worry that there are people out there who have plucked up the courage to get help, who are in a crisis situation, and who simply cannot access a service," Ms Lewis said.

She said the Health Service Executive, Tusla and the Department of Justice provide around 75% of the organisation's funding, for which One In Four were grateful.

However, she said that the demand from those seeking help for sexual violence, particularly people abused within families or in their community, had surpassed the resources available.

She said it was a "mammoth task" to fund to fill the gap in State funding.

Ms Lewis also said that One In Four would welcome increased statutory funding, but that in reality "all the agencies who work in the field of sexual violence are struggling for resources".