The High Court has refused an application by a Sinn Féin TD seeking to have the Referendum Commission withdraw some remarks it made earlier this month.
The case centred on statements made by the commission about whether Ireland has a veto over the establishment of the EU's permanent bailout fund, the European Stability Mechanism.
The statements relating to the ESM were made on 3 May and 18 May.
In the High Court this morning, Mr Justice Gerard Hogan said there was no difference between two statements by the commission, as had been alleged.
He said the commission had acted in a sincere, genuine and measured way to the best of what he called its ''very considerable ability''.
In an affidavit, Sinn Féin TD Pearse Doherty had alleged that some of the commission's statements were inaccurate and were biased towards the Yes side.
The outcome of the case has no bearing on the holding of tomorrow's referendum.
Last night, Mr Doherty's Senior Counsel, Richard Humphreys, told the court that the first statement got a lot of attention in the media, gave prominence to the Yes argument and the words used gave the impression Ireland could not veto the ESM.
Mr Humphreys said the statement was not accurate.
He said a second statement by the commission indicated it was still open to Ireland to use the veto.
Michael Collins, Senior Counsel for the Referendum Commission, said the application was "flawed" and "misconceived".
He said there was no inconsistency between the two statements and there was nothing wrong with the first statement.
Mr Collins also said that Mr Doherty had waited until the eve of the broadcast moratorium, which started at 2pm today, to bring his application although the first statement was made on 3 May.
Speaking on RTÉ's Morning Ireland, Mr Doherty said he had not wanted to go to the courts, but claimed the Referendum Commission had not replied to two letters from his party.
However, Tánaiste Eamon Gilmore described the court challenge as a "stunt".
"I think that this is a last-minute publicity stunt by Sinn Féin to throw a bit of sand in the eyes of everybody and to create additional confusion before the actual vote takes place," Mr Gilmore said.
He also categorically ruled out the possibility of a second referendum on the fiscal treaty should it be rejected in tomorrow's vote.
Mary Lou McDonald adamant Govt could veto ESM
Mary Lou McDonald says Sinn Féin stands over its position that the Government can veto the establishment of the European Stability Mechanism, despite today's High Court ruling.
During the final debate of the fiscal treaty campaign on RTÉ's News at One, she said Sinn Féin still believes the Government can insist on the removal of the clause linking access to the ESM to the ratification of the fiscal treaty, by using a veto to block the establishment of the ESM.
Ms McDonald said that Judge Hogan ruled in court this morning that the Referendum Commission's verdict - that only those countries that ratify the treaty can access the fund - was a legitimate view, but not a definitive one.
However, Fine Gael's Simon Coveney said that it is too late now to use the veto.
He said the Government had the option of a veto when the treaty was being negotiated but it chose not to use it.
He asked why the Government would want to veto the setting up of a rescue fund that it might need to access.
He claimed Sinn Féin had lost the argument on the key issues and was now misleading people by taking a court case, which he described as a political stunt.
But Ms McDonald said Judge Hogan did not take the view that their case was a stunt, and had pointed out that there were legitimate views on both sides.
Meanwhile, voting continues today on islands off the coast of Co Galway.
Over 1,100 people are eligible to vote on the three Aran Islands and on Inishbofin.
Over 600 people are eligible on Inis Mór, which has two polling stations.
211 people can vote on Inis Oirr and about 160 voters are eligible on Inis Meáin and Inishbofin.