Sinn Féin TD for Kildare South Patricia Ryan has resigned from the party.
The move comes ahead of the party's selection convention for the constituency next week.
Sinn Féin Chief Whip Pádraig MacLochlainn said he was disappointed with the decision, and described Ms Ryan as a valued member of the party.
"We encouraged Patricia to seek the nomination but she was unwilling to do so," he said.
Me Ryan made headlines when she was elected in 2020 after having been on a family holiday during the election campaign.
Sinn Féin has so far selected more than 50 candidates to run in the upcoming election.
The party said it will not make a final decision on its overall number of candidates for some time yet, amid suggestions that it could ultimately run up to 64 candidates.
It is understood that Ms Ryan was likely to face competition at the selection convention from Kildare Councillor Shónagh Ní Raghallaigh.
Nominations for that convention are set to open tomorrow.
The TD's decision follows on from what were described as "difficulties" she was experiencing within the party locally.
