The Green Party's deputy leader, Catherine Martin, has declared her intention to run for the leadership of the party.
She has written to around 100 party members today confirming she will stand against Eamon Ryan.
However, Ms Martin - TD for Dublin Rathdown - has asked that no campaigning takes place until the programme for government talks have concluded.
Those members contacted include people who have nominated her ahead of tomorrow's deadline, and those who have contacted her directly asking that she run for the position.
Sources claim she has received over 200 nominations - four times what is required.
"After careful consideration, I have decided to accept your nomination and allow my name to go forward as a candidate to contest the party's leadership election," she said in letters sent to supporters.
"I am both grateful for and humbled by the many nominations I have received."
Deputy Martin said the timing of the leadership election is "less than ideal" given that government formation talks are entering a critical phase.
"I will not engage in any election canvassing and campaigning whatsoever, nor will I do any media in respect of the leadership contest until such time as the crucial Programme for Government negotiations have concluded uninterrupted and our members have considered and voted on any deal which may arise," she said.
"Once this comes to a full conclusion, I look forward to sharing with you my vision for our party. I relish engaging in a deep, vibrant and enthusiastic conversation with all Green Party members about the future of our party and how we can best serve the people of Ireland and safeguard our planet," she said.
Last month, four Green Party councillors wrote to Ms Martin "urging" her to challenge Eamon Ryan for the leadership of the party.