Labour Party TD Ivana Bacik has confirmed that she will seek a nomination for the party leadership.
Last week, Alan Kelly announced that he was resigning as Labour leader after less than two years in the role.
He said the parliamentary party had lost collective confidence in his leadership.
Mr Kelly said he regretted that the party had not been able to make progress in the polls and did not get a bounce over the past two years.
He said the pandemic had restricted his ability to put forward his politics and that it had been hard for the party to move on from its period in government from 2011 to 2016.
Mr Kelly said he would continue as a TD for Tipperary, contesting the next election, and would stay on in his role until a new leader is appointed.
Ms Bacik, the sole candidate so far, wrote to party members this morning to inform them of her intention to seek a nomination.
She said she discussed her candidacy with Labour members in Dublin Bay South last Thursday and received their "overwhelming endorsement".
Speaking on RTÉ's News at One, she said there were a combination of factors that lead to Mr Kelly deciding to step down as leader of the party and it was a "collective and unanimous" decision.
Ms Bacik said it is important now that the party goes forward in a united fashion.
"Now more than ever we need Labour values front and centre, we need that centre left constructive voice for change to come through," she said.
Ms Bacik said the chief concern that she, Mr Kelly and all party members have now is that the party unites behind whoever becomes leader, and she wants to ensure that the party's message takes centre stage, as she says it did at last year's Dublin Bay South by-election.
"People saw through that binary Punch and Judy show of Sinn Féin or Fine Gael and instead wanted a third, alternative voice," she said.
Read: Is Ivana Bacik Labour's 'bit of gold'?
The Dublin Bay South TD was first elected to the Dáil in a by-election last July.
In her letter, she states that she won the by-election by standing on a "clear and constructive political message of seeking radical change for social and economic".
She said that he intends to speak with more councillors, area representatives and party members to seek their support for her candidacy.
