Four by-elections to fill Dáil seats left empty as a result of the European elections could take place on the same day in a "Super Friday" style election day as soon as the first half of November.
Fianna Fáil members and potential by-election candidates said they are preparing for the likely schedule as party leader Micheál Martin said "we anticipate the by-elections will happen before the general election".
As a result of May's European elections, four TDs - Fianna Fáil's Billy Kelleher in Cork North Central, two Independents4Change candidates Mick Wallace in Wexford and Clare Daly in Dublin Fingal, and Fine Gael's Frances Fitzgerald in Dublin Mid-West - left the Dáil earlier this year.
The election of the four now-former TDs to MEP roles has meant their Dáil seats have been empty since the new European parliament held its first session at the start of July.
Under existing Dáil rules, a by-election must be held to fill the seats within six months of them being vacated, meaning by-elections are necessary by the end of this year.
And, while speculation has been rife in recent months that a snap general election could instead be called - removing the need for by-elections - Fianna Fáil members said they believe a "Super Friday" vote in mid-November is now on the cards.
Fianna Fáil officials have stressed the party's national constituencies committee has yet to choose any candidates to run, in part because the by-elections themselves have not yet been called.
However, among the rumoured candidates are Lisa McDonald or Malcolm Byrne in Wexford; senator Lorraine Clifford Lee in Dublin Fingal; and Padraig O'Sullivan in Cork North Central - with Ms McDonald, Ms Clifford Lee and Mr O'Sullivan already chosen as general election candidates.
Among the Fianna Fáil members to publicly stake a claim for a by-election nomination is Mr Byrne, a poster of whom greeted visitors to Fianna Fáil's annual pre-Dáil think-in at Gorey, Co Wexford.
Should he be nominated, Mr Byrne said he will contest the race on his recent strong local and European election performance.
Asked about the upcoming by-elections, Mr Martin said he believes they will take place before any snap general election, adding: "We're preparing for the by-elections."