Heather Humphreys will temporarily take over as justice minister when Helen McEntee takes six months paid maternity leave, it has been confirmed.
Ms McEntee will remain as a member of Government without portfolio.
The Minister for Justice is to go on maternity leave on April 30.
Taoiseach Micheál Martin said Ms Humphreys will continue in her role as Minister for Social Protection.
Ms McEntee is the first Cabinet minister to be pregnant in office and is due her baby in May.
At present, public office holders have to claim sick leave when they take time off care for their newborn.
The Citizen's Assembly on Gender Equality is to produce proposals for maternity, paternity and other types of leave for public representatives in June.
Minister of State Hildegarde Naughton will be temporarily assigned to the Department of Justice and will be delegated responsibilities.
Minister McEntee will be re-appointed Minister for Justice when her period of maternity leave ends on November 1.
The Government said it believes that such reforms for maternity leave "are crucial" to increasing the participation of women in politics.
In a statement, Ms McEntee said that there are still "many barriers" to women entering politics.
"One of those barriers is the lack of maternity and paternity leave for councillors, TDs, senators and ministers," the minister added.
"Just as many young girls as young boys want to succeed in politics.
"Just as many girls as boys aspire to help our communities and our society by becoming public representatives and leaders.
"But they do not see the equality of their dreams and ambitions matched in equality of representation.
"I and my colleagues in Government are determined to change the current system for the next generation.
"I welcome the fact that the Citizen's Assembly on Gender Equality is considering the question of maternity, paternity and other types of leave for public representatives.
"The Assembly will produce its recommendations by the end of June.
"I would particularly like to thank Minister Humphreys for agreeing to be Minister for Justice, as well as Minister of State Naughton for taking a significant proportion of work within the Department of Justice, during the period of my leave.
"I am also extremely grateful to Minister of State for Law Reform James Browne for his help in assuming additional responsibilities in the Department of Justice during this period.
"I recently published the Justice Plan 2021, a plan to build a justice system that works for everyone.
"Ministers Humphreys, Naughton and Browne will focus on ensuring the implementation of the Plan during my leave.
"While I am very thankful to all my colleagues for their help and co-operation in accommodating me, it is clear that the lack of provision for maternity, paternity and other types of leave for those in public life is an issue that needs a long term solution."