Everywhere you go in Ireland the effects of the booming economy are evident.

The streets are full of shoppers and the noises of construction work.

Yet against this economic optimism some politicians have been sounding a note of caution about Europe.

Ireland is on the brink of change. For many years a beneficiary of European money it will soon become a net contributor, and as the EU becomes larger it will become one of a number of smaller countries.

Ministers voice doubts

In recent months two government ministers have called for a more critical debate on Europe. The Irish Minister for Arts, Sila de Valera, has argued that diversity is in danger of being forgotten in the push for further European integration.

I don't think a united states of Europe would be appropriate

Sila de Valera

In opinion polls support for the EU has always been high in Ireland. But some commentators believe the minister is picking up on the beginnings of a more questioning attitude.

Broad but shallow

There is no evidence of a deep, informed support for the EU says Professor Richard Sinnott at University College Dublin. While there's a broad perception that Ireland has benefited, he says that could change if challenged.

Economic growth is bringing rapid social change and that may mean an uncomfortable transition for Ireland.

We haven't laid out a model of what Europe will look like when it's finished

Ruari Quinn

A nation of emigrants is having to come to terms with migrant labour.

Ruari Quinn, leader of the opposition Labour Party says politicians have been too reluctant to tackle the more controversial aspects of change.

Not scepticism

It is not a scepticism in the sense of British Euro scepticism, he tells me, but simply an unease.

Mr Quinn says a frontier that stretches from Finland to the Algarve policed by people you don't know begins to raise questions.