The government has been urged to abolish fixed retirement ages for civil servants.
Public sector union FDA revealed research showing that more than one in four of its members wanted the right to work beyond the age of 65.
Almost half of FDA-affiliated civil servants aged 60 or above called for an end to fixed retirement ages in the survey.
FDA general secretary Jonathan Baume said: “Our results clearly show that civil servants are looking for flexibility around when they retire.
“It is time for the government to move with the times and update its policies by abolishing fixed retirement ages in government departments.”
Employees at most government departments – including all senior civil servants – are forced to retire at 65.
Age discrimination still exists in the Civil Service, according to the survey, although three-quarters of those aged 55 to 59, and two-thirds of those aged 60 and above, said they had never experienced it.
Those who had experienced ageism said that it included inconsiderate references to age, being patronised, and being demoted or marginalised, with one member being told they were “too old to be considered for certain promotions”.
Baume said: “While we welcome the finding that most members have not encountered age discrimination, inequality of any degree is unacceptable.”