The Sinn Féin president has said there are still several names in the hat when it comes to their presidential nomination.
Mary Lou McDonald claims the final decision will be made at a party convention but has not revealed who is up for consideration.
The party confirmed at the weekend that it wants to submit a candidate after Michael D Higgins' official announcement that he will seek a second term in office.
Mary Lou McDonald was asked if she thinks he is unbeatable.
"He is no doubt popular and he has stated his intention to go before the electorate and if that is the case all of that will be demonstrated in time, said Ms McDonald.
"But that's not the reason why there was a question mark over the election. The popularity of the incumbent, let's be frank, wasn't really the issue.
"The issue here was that Fianna Fáil and Fine Gael decided that they didn't want an election."
Yesterday, potential presidential election candidate Gerard Craughwell risked undermining his campaign by claiming the highest office in the country is a “meet and greet job” that has no impact on the general public.
Mr Craughwell made the comments as ex-taoiseach Bertie Ahern threw his support behind rumoured candidate Joan Freeman, and as speculation grew that businessmen Seán Gallagher and Gavin Duffy and political analyst Noel Whelan could enter the race.