Labour party leader Joan Burton has said she is "up for a fight" in the wake of an opinion poll which puts support for the party at just 4%.
The poll, prepared for a Sunday newspaper and apparently released early, shows popular support for Labour may have halved.
Party sources have cast doubt on the figure and suggested the poll may be what they call an outlier – an extreme value of a variable in a data set.
The poll was prepared by Behaviour and Attitudes for the Sunday Times and appeared online late yesterday.
The newspaper is investigating how it came to be published last night.
If confirmed, it would put the Labour party as low as 4%, with Fine Gael at 30%, Fianna Fáil at 22%, Sinn Féin at 15% and Independents and Others at 30%.
Within the figure for Independents, unaligned Independents are at 10%.
The Anti-Austerity Alliance/People Before Profit and the Independent Alliance are both at 5%, while Renua, the Green Party and the Social Democrats are on 3% each.
The Workers Party had 1% support, according to the survey.
Speaking in Waterford, Ms Burton said "I'm a fighter, and I'm up for a fight, I've never stood back from a fight".
Meanwhile, Paul Murphy of the Anti-Austerity Alliance took to social media last night, claiming the poll represented the first time the "socialist left" surpassed Labour.
Labour sources were bemused by the figures, suggesting the poll would at best prove to be an outlier amid the others due to be published over the weekend. However, it is a worrying start to a crucial seven days for the party.
Howlin does not believe poll
Minister for Public Expenditure and Reform Brendan Howlin has said he does not believe Labour are polling at 4%.
Conceding that he would have preferred Labour to have been "on a higher rating" in recent polls, the Minister said there had been "very little movement in public opinion" in relation to all the political parties.
Mr Howlin said he did not believe Labour support was even in "the ball park" of 4% in the polls.
He said people were not yet clear what they wanted, but said what they did not want was a "dolly mixture" in the Dáil, and would take the "safe option" on polling day.
Mr Howlin acknowledged there had been "a lack of spark" in the campaign to date, but said people only really had one option when it came to the next government - and that was Labour and Fine Gael.