Current Pensions Secretary Pat McFadden told the Commons that retaking the decision would not automatically lead to compensation.
“Retaking this decision should not be taken as an indication that government will necessarily decide that it should award financial redress,” he said.
The undisclosed evidence involved was a survey from 2007, and McFadden said that checks would be made to ensure other documents and surveys had not been missed. No timescale has been given for the work to be done.
“I understand that people are impatient for this matter to be resolved,” he said.
“It is important that we give it full and appropriate consideration.”
Angela Madden, who chairs Women Against State Pension Inequality (Waspi), said: “The government now knows it got it wrong and we are pleased they are now trying to do it properly.
“We hope they also try to do it quickly.”
She added that the “only correct thing to do” was to compensate those affected immediately.