The Rape Crisis Network took more than 13,000 calls to its helpline last year, despite a 70% cut in its funding.
The RCNI says the withdrawal in funding by the Child and Family Agency, Tusla, took effect last year.
Executive Director of RCNI, Clíona Saidléar, said: "RCNI has received no funding from the Child and Family Agency Tusla for two years. Last year, a cumulative 70 per cent cut to our funding took effect and our core funding from Tusla was completely withdrawn.
"Because of this, we were unable to continue to provide the support we used to to the sector in relation to policy and guidance. We have worked hard to prioritse and support key policy areas but there is a gap opening up which needs to be urgently addressed.
"RCNI made the decision to continue operating our globally innovative and best practice data collection system without the support of Tusla, as there is no other mechanism possible to give voice to these survivors who are otherwise silenced."
The network also says more survivors reported satisfaction with the Gardaí last year than in 2014.
However, 65% of survivors had not reported their rape to Gardaí before contacting the rape crisis network.
Ms Saidléar said: "On all three indicators: sensitivity; contact levels; and information, more survivors were satisfied with their experience with the Gardaí than in 2014.
"The report shows that 69% of survivors who filed a complaint with the Gardaí felt that they were treated in a sensitive manner, that their complaint was taken seriously and the Gardaí were attentive, sympathetic and supportive. This is a six-point increase from the previous year."