Rebel Fine Gael TD Lucinda Creighton has denied she has already renewed her membership of the party for another year.
Fine Gael members are due to renew their annual party membership at the moment.
Ms Creighton is due to make a decision on the matter following her expulsion from the Fine Gael parliamentary party and setting up of the Reform Alliance.
Taoiseach Enda Kenny told Ms Creighton in the Dail he was "delighted" to see she had renewed her party membership.
But Ms Creighton replied that it wasn't true.
"I understood you have," Mr Kenny replied.
The former European Affairs Minister has another six weeks to decide if she wants to remain a member of the party.