16 members of the Social Democrats, including two councillors, are calling for a change of leadership.
They've asked the party's national executive to call a leadership election.
They say co-leaders Catherine Murphy and Roisin Shortall have done an 'exceptional job'.
However, they say it's time for change ahead of the general and local elections in 2024 and 2025.
In a statement responding to the call, the Social Democrats parliamentary party said it remains "united behind co-leaders Catherine Murphy and Róisín Shortall".
They said: "Under their leadership, the party tripled its number of TDs in the 2020 General Election and we are all focused on continuing our important work holding the government to account, particularly in the areas of housing, health and climate action.
"We are hugely ambitious for the party – and building a strong social democratic alternative in Ireland."
The Social Democrats were founded in 2015 by Catherine Murphy, Róisín Shortall and Stephen Donnelly, with all three serving as co-leaders.
Stephen Donnelly resigned from the party in 2016 and later joined Fianna Fáil, while Deputies Shortall and Murphy have remained as co-leaders.
The party won six Dáil seats in last year's general election, and have 18 representatives in local authorities.
Party leaders and TDs have ruled out calls from Labour leader Alan Kelly for the two parties to merge, while they also refused to join any Fine Gael / Fianna Fáil coalition after the last election.
