Campaigner Vicky Phelan has described the establishment of a long-waited CervicalCheck tribunal without proper consultation with those impacted as "a slap in the face".
Calling for a meeting with health minister, Stephen Donnelly, Ms Phelan said: "Why is it so hard to do what's right for women who have already been failed by the State?"
The health minister brought a memo to Cabinet earlier this week proposing that the tribunal, which will investigate negligence in the State's cancer screening service, begin on October 27.
However, Ms Phelan said she was "left reeling" when she learned of this.
"To announce that this tribunal is going to be established in the next seven days, it just feels like a slap in the face."
She said campaigners had met the Health Minister seven weeks and raised concerns around the setting up of the tribunal.
"We left the meeting encouraged that there would be further consultation," she told RTÉ's Morning Ireland programme.
Instead, Ms Phelan said the minister had "forged ahead" without taking their concerns on board.
The 221+ Cervical Check Patient Support Group had made a number of requests including that any tribunal be non-adversarial in nature.
They also believe that women who suffer a recurrence of their cancer should be allowed to return to the tribunal similar to applicants who came before the Hepatitis C and HIV Compensation tribunals.
It is exactly one year ago today since Leo Varadkar delivered a State apology to the women impacted by the scandal and their families.
"That was a momentous day for us," Ms Phelan said.
"We felt it marked the beginning of a healing process for us, we felt heard, unfortunately, this week when we read the letter from Minister Donnelly we felt anything but heard.
"We simply do not understand why the minister would not take the opportunity to work with us to make the tribunal something that our members might be encouraged to engage with."
Mr Donnelly said he would meet the 221+ group before next Tuesday when the Tribunal is due to begin. However, he said, it would be "impossible" to set up a system that is completely non-adversarial.
"It is understood by everyone involved that claims are paid when negligence is established, and if negligence is to be established people have to be able to ask questions and people have to be able to disagree."
But, he added: "Everything we're doing is to try and find the best way forward for the 221+ group, it's why the tribunal was established."