All Civil Service employees - both male and female - will be offered equal parental pay and support from next year, Nick Clegg will announce this week.
The change means that fathers will now be able to benefit from enhanced pay for shared parental leave - if both parents decide to divide the time up - as mothers currently do.
Following a previous announcement by the Deputy Prime Minister last year, new parents will already have the choice over how they split their statutory entitlement from April.
But there will be no onus on employers offering occupational maternity schemes above and beyond that to do so on an equal basis.
This means that while fathers have the right to take leave, they may be discouraged from doing so if they do not receive any occupational benefits and have a partner who does.
Mr Clegg hopes that equalising occupational support at the Civil Service, also from April, will encourage other public and private sector organisations to follow suit.
In a speech, the Liberal Democrat leader will say: “Evidence shows promoting flexible working patterns like this can help boost employee productivity, loyalty and retention.
“This means more fathers will be able to afford to take time off to spend caring for their new born children.
“More widely, I want to see this change blaze a trail for other public and private sector organisations to follow - making this option the norm for more working families and increasing the opportunities available to both sexes to earn and care across our society.”