Government plans to scrap the fixed retirement age next year have come under fire from business leaders.
Currently, employers can force staff to retire at the age of 65 regardless of their circumstances and without having to pay any financial compensation.
Under the government's consultation proposals, the default retirement age (DRA) would begin to be phased out from April 2011 and come to an end by October next year.
Ministers said the move was designed to give people more choice as they enjoy longer and healthier lives.
But Katja Hall, director of employment policy at the Confederation of British Industry, said: "Our fear is that they will keep on going, perhaps they haven't quite saved enough for their pension, so they feel they have no choice but to keep on going.
"And the employer is left in a very difficult situation where they either have to start performance managing that individual, which is not a pleasant process, or just keep them on when they're not really performing in their job."
In January, the Equality and Human Rights Commission argued that abolishing the DRA would inject £15 billion into the economy.