The Women Against State Pension Inequality (Waspi) campaign described the government’s decision as an “insult”.
“The government has today made an unprecedented political choice to ignore the clear recommendations of an independent watchdog,” said Angela Madden, who chairs the campaign group.
“This is a bizarre and totally unjustified move which will leave everyone asking what the point of an ombudsman is if ministers can simply ignore their decisions.”
The Waspi campaign had called for payments of at least £10,000 each.
But Kendall said there was evidence that there was “considerable awareness” of the changes to the pension age, and sending letters earlier would not have made a difference to their ability to make retirement choices.
She also said that there was no evidence of “direct financial loss” resulting from the government’s decision.
“Given the vast majority of women knew the state pension age was increasing, the government does not believe paying a flat rate to all women at a cost of up to £10.5bn would be fair or proportionate to taxpayers,” she said.
Prime Minister Sir Keir Starmer said he understood the concern of the Waspi women, but had to take into account whether it was right “to impose a further burden on the taxpayer”.