TAOISEACH BRIAN Cowen warned yesterday that a No vote against the Lisbon Treaty next week could result in serious economic consequences for the State.
As well as isolating Ireland's position within the European Union, Mr Cowen warned that a rejection of the treaty could also threaten foreign investment.
"The consequences of a No vote are increased uncertainty as to the direction of the EU and what's Ireland's role in it will be," Mr Cowen said, during a campaign tour of Limerick and Tipperary.
"I think we're facing into more uncertain times in terms of the international economy, we don't need to add to our burden of trying to deal with that issue by voting No."
On the issue of foreign direct investment, he said any perception that Ireland was turning its back on the European project could have adverse consequences.
"What signal are we sending to the international investment community if we are not interested in the continuing integration of the European economy which has brought such success to our own economic affairs," he said.
"Remember, there are many corporate headquarters around the world which have invested here - around 1,000-plus companies - because of the fact that we are centrally involved in the European Union and provide a base and a market, not only for Europe but for further afield."
Facing into the final week of the campaign, he acknowledged there was still confusion over many of the issues but insisted that political parties and lobby groups were doing their best to inform the electorate.
He also defended the performance of the Referendum Commission, which was initially unable to answer questions at a press conference this week over the rules governing a pledge contained in the treaty under which EU states are expected to come to the aid of one another.
"I think on the basic issues, on the main issues, the Referendum Commission has been admirably clear in relation to what it has to say on the basic issues," he said.
Mr Cowen said there was no question that it was in the best interests of the country that Ireland remained at the heart of the EU.
The benefits included increased goodwill from EU neighbours and greater influence in policy-making.
The dangers, he said, included losing much of this goodwill and creating a "crisis" over the future direction of the EU.
"The stronger the EU institutions are and the stronger the European economy is, the stronger the opportunity for the Irish economy to grasp on to that and get the benefits which we have so visibly seen over the last decade."
When questioned over why the Yes campaign had not been able to comprehensively tackle many of the fears raised by the No campaign, he insisted that the No camp's arguments did not stand up.
"I think their [the No campaign's] arguments have been dismissed and demolished, all right. The problem is they keep asserting them, even when you confirm that the treaty has nothing to do with abortion, corporation tax or other issues," he said.
"I have great belief in the common sense of the people. This sort of doomsday scenario has been presented in every European referendum I've fought over the last 20 years. It's the same people, in the main, the same arguments, the same conspiracy theories."