"We got to make old people productive. And I don't think there should be a retirement age,"
Singapore's current retirement age is 62, but it will be extended to 65 in 2012 as the workforce ages.
Mr Lee believed Singaporeans would soon realise the benefits of working into old age.
"If you keep doing what you've been doing for almost the whole of your life, chances are you will stay interested and engaged in life," he said, adding that thoughts of feeling old could negatively impact a person's longevity.
He joked that if he was suddenly asked to stop working, "I think I will just shrivel up, face the wall and just die".