The Northern Ireland Assembly has raised the age at which women can get a state pension.
By 2018, women will have to be 65 to draw a state pension. An estimated 7,000 women could be affected.
In 2020, the age for both female and male state pensions rises to 66.
Social Development Minister Nelson McCausland said concerns had been raised with Pensions Secretary Iain Duncan Smith but changes to a bill to introduce the rise were not accepted.
He said amendments had been "well-intentioned" and were aimed at "relieving the impact for people in Northern Ireland".
"These were not accepted on grounds of cost and the maintenance of parity," he said.
"They reflected the level of concern felt by members about the increases in the state pension age and I share those concerns."
Mickey Brady, the deputy committee chair of the social development committee, said the majority of clauses in the bill were "extremely technical in nature" and all members had "shared concerns about the bill".
"The pension age between men and women should be the same, and the committee recognises and accepts that, however, where members had concerns about this related to when it took effect," he said.
Ulster Unionist Michael Copeland said the change could affect "some 7,000 women in Northern Ireland".
"It is a matter of regret for all of us that they will now have less than the 15 years of preparation time recommended," he said.
Mark Durkan of the SDLP opposed the final stage of the bill.
"My regret stems from my belief that this assembly has, in rejecting amendments brought forward at earlier stages of the bill, missed an opportunity, not only to reduce the negative impact that this legislation will have on so many of our citizens, and on society as a whole, but also an opportunity for this assembly to show that it is capable of challenging the shackles of parity," he said.
Judith Cochrane of the Alliance Party said she was sympathetic to those who would have less time to prepare financially.
"We do need to be realistic with this issue, and from the information that I have, I believe that Northern Ireland simply cannot afford to break parity on this," she said.