The latest UK-wide estimates suggest over half (56%) of patients are now waiting over 52 weeks.
Women who have spoken to BBC News NI said waiting up to five years just to be seen by a consultant and even longer for surgery is not unusual.
Among those waiting is Marie Mullan from Belfast, who said she waited 20 years for a diagnosis.
“During that time I was told mainly by male doctors that it was just period pain and I would have to live with it,” she said.
Mullan, who was a teacher, had to take medical retirement because she said she couldn’t physically work.
“My life has been ruined waiting for treatment for endometriosis,” she said.
“The pain is chronic – at one stage I was so bloated and unable to eat they thought I may have ovarian cancer.
“Gynae issues and especially endometriosis is just not prioritised – it is debilitating and life changing but just not taken seriously by the health service.”
While she did eventually have surgery, she said it wasn’t successful and she has been back on the waiting list for almost two years.
The RCOG has said 2026 must be a turning point for women waiting for gynaecology care.
It has called for faster, more decisive action to support women already waiting and to tackle the underlying capacity challenges driving long delays in Northern Ireland.