Allegations that the main opposition candidate in the Mexican presidential election, Mr Vincente Fox, received illegal donations, including some channelled through the Smurfit paper company, have marked the closing stages of a hectic campaign.
Mr Fox of the centre-right PAN is in a neck-and-neck race with Mr Francisco Labastida, the candidate of the Institutional Revolutionary Party (PRI), which has held the presidency for an uninterrupted 71 years.
Mr Fox has been accused by Mr Labastida and a third opponent, Mr Cuauhtemoc Cardenas of the left-wing PRD, of receiving funding from abroad which is illegal under Mexican law. Mr Fox has strongly denied the charge.
Among the foreign companies alleged to have helped finance Mr Fox's campaign are Coca Cola for whom he was once a senior executive in Mexico, and Microsoft. Three newspapers have also carried reports that Mr Fox received up to $95 million from the former Mexican president, Mr Carlos Salinas, and that the money was channelled through the Smurfit organisation which has a large operation in Mexico.
Mr Salinas lived in Dublin for several years after he left office in 1994.
Mr Jose Pontones, a senior Smurfit executive in Mexico, has written to the newspapers concerned strongly denying the allegations of money laundering to help Mr Fox. Mr Pontones has demanded a retraction from the newspapers, two of which are owned by the Irish honorary consul in Mexico, Mr Romulo O Farrill, an extremely wealthy media magnate who had entertained the former Taoiseach, Mr Albert Reynolds, on his yacht, several years ago during a visit to Mexico.
Mr Pontones also said that rumours that Mr Salinas had met Mr Michael Smurfit were untrue. The company had checked to see if legitimate transfers from Ireland to the Mexican operation corresponded to the amounts alleged to have been given to Mr Fox but this was not the case. The allegations against Smurfits had been made by pro-PRI newspaper columnists and not as news reports.
Mr Salinas, who may now have discreetly returned to Mexico, is a discredited figure following revelations of corruption during his presidency. His brother, Raul, is now serving a lengthy prison sentence for corruption.
Active campaigning in Sunday's election ended with the main candidates holding huge rallies in their home states. Hundreds of foreign observers are arriving. The election could result in the PRI losing the presidency for the first time since it was founded in 1929.
Mr Fox has threatened to challenge the result if he loses by less than 10 per cent because the PRI in the past had the reputation of practising widescale fraud. But the independent electoral institute has confidently predicted a clean election and counting of votes.