Social Democrats co-founder Stephen Donnelly says there has not been a seismic shift in voting in the general election.
The new party has gained three seats in the 32nd Dáil - with the party's co-leaders Roisín Shortall, Catherine Murphy and Stephen Donnelly all elected on the first counts in their respective constituencies.
Donnelly, who topped the poll in Wicklow, says that while there's a cultural difference between Fine Gael and Fianna Fáil, their policies are similar - and that's what the majority of voters opted for.
Speaking on The Right Hook, Deputy Donelly said, "from a policy perspective, there's not that much difference.
"Fine Gael are a centre-right and increasingly right wing, in my opinion, socially conservative party. Fianna Fáil move to either side... but they're basically socially conservative as well.
"So if you take those two parties... say, by European or international standards... they're basically the same," he added.
Donnelly observed that "everybody is saying this is a seismic shift, it's a political earthquake - it's not at all... There's been a perfectly consistent fall in the combined votes of those two parties from the 60s - it just so happens this is the first election that the combined vote is less than 50%.
"What we're seeing is not that big a change - it's the consequence of something that has been happening in Ireland for the last 50 - 60 years," he suggested.