'Now Irish people feel part of the European process'
And the Taoiseach hailed the electorate for taking the historic step that paves the way for European Union enlargement.
European barriers are coming to an end with Ireland's decision to endorse the Nice Treaty, Mr Ahern said.
It was now vital that the effort was made to consult and engage with the electorate on European issues, Ms Harney said.
"I think on the last occasion, quite honestly, we took the people for granted," she said.
Stating that far greater transparency was needed in Europe, Ms Harney said that meetings of the EU Council of Ministers should be held in public.
Describing the passing of the referendum as a good result for the country, Ms Harney paid tribute to all the groups that campaigned for a Yes vote.
In particular, she acknowledged the role played by Fine Gael and Labour, who had adopted a responsible attitude, she said.
Ireland had never sought to gain at the expense of others and the country did not want to have the blocking of enlargement on its shoulders, Ms Harney said.
Reiterating that the referendum strengthened Irish neutrality, she said Ireland could not join a common defence alliance without consulting the people.
"You know and I know that Ireland will never join NATO," she said.
Fine Gael leader Enda Kenny said that, following Nice, it was vital that ordinary people remained involved in EU affairs.
The Government needed to take people's concerns on board and explain issues properly, he said. Information campaigns needed to be properly resourced and the Forum on Europe needed to continue its work, Mr Kenny said.
"Out of all of this, Irish people feel part of the European process," he said.
Accepting the Tánaiste's comments on the Opposition's stance in the Referendum, Mr Kenny said the gloves would not come off in terms of criticism of the Government.
Labour leader Ruairi Quinn said the passing of the Nice Treaty did not signal a move towards federalism in the EU.
"It's not right [to say] that we are going into a superstate," Mr Quinn said.
The EU could not be compared to the United States, Canada or Australia, all federal states, he said, and the central building block in the EU would remain the nation state.
In reference to the winner of the Labour leadership contest being confirmed later this week, Mr Quinn said he was delighted the last campaign he was involved in as party leader was so resolutely successful.
The philosophical debate about Ireland's engagement with the EU should ideally have taken place 20 years ago, he said. Unease about the EU's future direction was understandable.
Health Minister Micheál Martin said the economic arguments put forward in the campaign played a vital role
because they had a resonance with voters.
The Referendum illustrated the importance of having an active campaign and the result was highly significant in terms of Ireland's future, he said.


