Cooper said: "I can understand that employees in their thirties might have to plan now to retire later [than expected] but I don't think it is fair to tell people in their fifties to rip their retirement plans up."
Cooper's announcement came in response to shadow chancellor George Osborne's speech at the Conservative Party Conference in Manchester last week, where he explained this would be the plan if a Conservative government were to be elected next year.
Speaking a week later but at the same venue as Osborne, at the National Association of Pension Funds Annual Conference, Cooper also suggested the default retirement age of 65 should be removed.
Currently employers are controversially allowed by law to end employees' contracts of employment when they reach the age of 65.
But Cooper said: "The default retirement age was brought in for good reason but now it needs to be reviewed. I have met employees who want to work on into their seventies, and some who would prefer to work part time. Today we are launching a call for evidence on the topic of retirement age."
