The Taoiseach has rejected suggestions that the poll on the Lisbon Treaty might be influenced by the controversy surrounding him.
He was speaking after talks with Slovenia's Prime Minister Janez Jansa in Ljubljana.
Mr Ahern told a news conference that the European referendum would probably be held in June.
Asked whether it might become a vote of confidence in himself given recent events, he said he did not think that was likely.
The Taoiseach said that most political parties in the Dáil were in favour of a Yes vote, as were some 500m people in Europe.
He said the issue of the Mahon Tribunal had not been raised at any of the meetings about Europe he had attended.
Slovenia currently holds the EU presidency, and Mr Ahern's talks with Prime Minister Jansa centred on plans for the forthcoming European Council, the situation in Kosovo and bilateral issues between the two countries.
Tomorrow the Taoiseach flies to Vienna where he will address a meeting of the OSCE, the international body whose stated aim is conflict prevention and political stability in Europe.
