Ms Collins quit the Pontifical Commission for the Protection of Minors last March in frustration at lack of action on its recommendations.
Another high-profile resignation followed and the commission finished out its three-year term last December with uncertainty surrounding its future.
Pope Francis said at the weekend the commission was reconvening, but with only two of the original lay members.
Ms Collins said this was despite members asking to be returned to continue their work. She said the clerical members were invited back.
“My confidence in the commission to bring any radical change to the Church would not be there any longer,” she said.
“I did have great confidence in the commission and the members that were in it and when I resigned I still had confidence in it, but I think with the turnover now and the people I’ve seen leaving voluntarily or not being reappointed, it doesn’t fill me with hope at all.”
The 16-member commission had six working groups and four of the lay leaders were gone, Ms Collins said, while of the four members who were on the key working group for the healing and care of survivors, all three lay members were gone.
“The only original member left is a religious sister,” said Ms Collins. “I’m sure the people coming on to the commission are very worthy people but they’re starting at scratch again. A lot of the expertise and skill that had been built over the three years has been lost.”
Pope Francis, announcing the new commission under the leadership of US Cardinal Sean O’Malley, promised victims would be given a greater say in it work.
However, Ms Collins said the Vatican saw the previous commission as “too independent” and she did not see that attitude changing. She said the way to prove otherwise was for its recommendations to be implemented.
“Things such as the guidelines template for child protection which was to be made universal to all the churches around the world,” she said. “The commission drew it up and it was approved but it has never been disseminated.
“Also the issue of accountability of bishops. A tribunal was recommended but wasn’t implemented and the responsibility for the disciplining of bishops has been given back to the Conference of Bishops so they’re looking after their own.”
Ms Collins said she was disappointed that Pope Francis had not stood up to the Curia — the Vatican governing body.
“He did not get in behind the initiatives and ensure that they were implemented so there wasn’t the force there that was needed,” she said.
“If you ask a group of experts to advise you and they give you their advice and you think it’s good advice, it’s up to you then to ensure that it happens.”
Pope Francis will visit Ireland in August for the World Meeting of Families but Ms Collins said she did not think there would be an opportunity to raise her concerns.
“He never met with the members other than to shake our hands after Mass,” she said.
Ms Collins was appointed to the original commission because of her campaigning work for victims in Ireland after she challenged the late Cardinal Desmond Connell over his failure to tackle paedophile priests such as the hospital chaplain who attacked her when she was 13.
She said she had committed to a number of training sessions with the members and had one more to fulfill.
“Then I won’t have any more association with the commission,” she said. “I will be cutting my ties completely.”