The Home Office and other government departments are moving from a defined benefit (DB) to career average pension scheme and increasing their retirement ages from 60 to 65 years from 1 July.
The move, which comes after a two-year consultation with trade unions is intended to reflect the UK's ageing working population.
John Marsh, group HR director at the Home Office, said: "The increased pension age for new entrants is very much in recognition of the longer working age for the general population."
The new offering will also entail members contributing to the running costs of the DB scheme should they increase.
The amount members will be expected to contribute is still being negotiated, with union input.