Dave Prentis, general secretary of Unison, said: "The Government seems hard wired into attacking the most vulnerable in society. Workers who have to rely on their state pension to make ends meet will have no option but to carry on going for another year – whatever the cost to their health – but the better off will be able to retire earlier. One rule for the rich, another for the poor.
"It may be a choice for the fit and healthy to keep on going for another year at work, but for some work takes a terrible toll on their health.
"Many workers across the public and private sector do very physically demanding jobs where carrying on until 66 is not a safe or practical option.
"You cannot expect paramedics to carry patients down flights of stairs or out from under cars into their late sixties. The same pressures fall on nurses, street cleaners, gardeners, home care workers, cooks, road diggers, engineers and cleaners not to mention the mental stress of working in very pressured environments like social work, in schools and universities.
"This lack of joined-up thinking will pile more misery on workers, as well as increasing the long-term costs to our NHS."
And Adam Marshall, director of policy at the British Chambers of Commerce, added: "It is strange the Government has pledged to reduce the burden of employment law - while at the same time proposing to restrict businesses' ability to manage their workforce by abolishing the default retirement age. Business agrees that the default retirement age is currently too low - and needs to rise for both deficit reduction and fairness reasons.
"But if ministers want to make a positive change, they should either raise the default retirement age in line with the state pension age or offer employers a new dismissal route that helps business manage their workforce regardless of age."
