Taoiseach Brian Cowen has said the polices of Sinn Féin and the Socialist Party will not bring one job or €1 of investment to Dublin and their election would send out the wrong message to foreign investors.
Mr Cowen was speaking at a press conference with the Fianna Fáil candidates for the European Parliament in Dublin.
For more on the elections visit RTÉ.ie/elections
Recent opinion polls have shown the sitting Fianna Fáil MEP, Eoin Ryan, in a tight race for the third seat in the constituency with Mary Lou McDonald of Sinn Féin and Joe Higgins of the Socialist Party.
Mr Cowen said he was 'strongly urging' Dubliners to elect pro-European and pro-enterprise MEPs.
Elsewhere, European leaders stepped up their bid to persuade people to vote for the EU parliament this week.
French President Nicolas Sarkozy and German Chancellor Angela Merkel issued a joint plea to voters, saying a strong Parliament was essential to confront the economic crisis.
The two leaders said they want 'a strong Europe that protects' its people and called for 'all Europeans to vote' in the statement, published by the Journal du Dimanche newspaper in France and Die Welt am Sonntag in Germany.
A 'strong Europe does not necessarily mean more powers for the European Union, even more European legislation or even more financial means,' said Ms Merkel and Mr Sarkozy.
First steps 'to assure real European regulation in the financial sector, based on coordination and cooperation between regulators' should be taken at the next EU summit in June, they said.
They also gave strong backing to the Lisbon Treaty in the statement.
'Europe must play a leading role in the world. For that, it must have efficient institutions. That is why we need the Lisbon Treaty,' they said.
Countries go to the polls on 4-7 June.
Ireland votes on Friday, 5 June, the same day as the local elections, and two bye-elections - in Dublin Central and Dublin South.
