Eamon Ryan is expected to continue as Minister for Transport, Climate, Environment and Communications when he steps down as leader of the Green Party.
Mr Ryan is to announce his decision to step away from the party leadership following a meeting of the Cabinet.
He has spoken to the two other coalition Government leaders, Simon Harris and Micheál Martin, and has also informed members of his parliamentary party.
Mr Ryan has led the party since 2011 and retained the role after a leadership contest in 2020 when he defeated Catherine Martin by 994 votes to 946.
Ms Martin, who is the current deputy leader of the Green Party, is seen as the front runner to replace him as leader.
Read More: Live updates
Mr Ryan was first elected to the Dáil in 2002 in what was then the Dublin South constituency, and served as minister for communications from 2007 to 2011.
He lost his Dáil seat in 2011 but was re-elected in Dublin Bay South in 2016.
His announcement comes after both of the Green Party’s MEPs – Ciarán Cuffe and Grace O’Sullivan – lost their seats in the European elections.
The number of Green Party councillors was also halved in the local elections.
Mr Ryan is the second leader of a coalition party to step down this year, after former taoiseach Leo Varadkar stepped away from that role, and stepped down as Fine Gael leader, in April.
