The latest opinion poll in the Republic suggests an increased likelihood of a Sinn Féin-Fianna Fáil coalition after the next general election.
With little over a maximum of 18 months until the next Dáil election, support for Sinn Féin stands at 34 per cent, a three point increase on last month's corresponding poll.
The survey shows Mary Lou McDonald's party is steadily regaining ground, having registered support of 29 per cent in March.
The latest polling, carried out by Ireland Thinks for the Sunday Independent, puts Fine Gael on an unchanged 19 per cent and Fianna Fáil down one point to 18 per cent, with the Greens on 5 per cent, up two percentage points.
The Social Democrats are at 5 per cent, down one point; Labour is at 4 per cent, up two points; Solidarity-People Before Profit is on 3 per down one point; and Aontú is on 2 per cent, down one point.
Taoiseach Leo Varadkar recently said there was a "very good chance" the current coalition partners would be re-elected.
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However, the polling indicates a greater level of support for a Sinn Féin-Fianna Fáil coalition (39 per cent) compared to the incumbents' support of 36 per cent.
The taoiseach has also recently denied that there are any plans for an early general election.
Local and European elections are to be held in May or June next year, while a general election must be called by spring 2025.
Mr Varadkar has said he intends to lead his party into the next general election and hopes to form a government afterwards - and has categorically ruled out a coalition with Sinn Fein.
On the prospects of historic rivals Sinn Féin and Fianna Fáil joining forces in office, former government adviser Derek Mooney suggested a second election was more likely.
He told The Irish News that "most of the spinning" about Fianna Fáil propping up Sinn Féin in future came from "sources close to Fine Gael".
"You can see what Fine Gael is up to – the spin helps FG to push itself as the party you must back to stop Sinn Féin," he said.
Mr Mooney, who left Fianna Fáil in protest at its decision to join the current administration, said it wasn't inevitable that Micheál Martin's party would end up in third place.
"While Fianna Fáil is well below where it was in 2019, the latest polls show Fine Gael as the party most in trouble," he said.
He said there was a "real risk" that a number of Fianna Fáil TDs would leave the party "rather than put Sinn Féin into office and place their own seats in jeopardy".
"There may even be a few Sinn Féin TDs who would see a return of Fianna Fáil ministers to office as a bridge too far," he said.
"Either way, there would only have a handful of potential defectors on either side to make the option impractical – right now my belief is that the most likely outcome of the next Irish general election is another election, with new faces at the top of the two older parties."
However, Irish News columnist Chris Donnelly said it looked likely that "Sinn Féin’s route to government in Dublin is going to have to involve coalescing with a junior partner".
"Cobbling together a majority amongst left wing parties is unlikely to prove possible, so inevitably the focus will be on a SF/FF coalition and while neither party will be overjoyed at the prospect, the numbers post-election may show it's the only realistic option," he said.
"I find it hard to believe Mary Lou McDonald would say no, not least as it would be a coalition with Sinn Féin as the dominant party, seeking to set the agenda, beginning with the confirmation of McDonald as the first female taoiseach in the history of the state."
Mr Donnelly said that although the Micheál Martin has publicly stated opposition to serving with Sinn Féin, there were other senior figures in Fianna Fáil who would "embrace the move".
