Taoiseach Enda Kenny “couldn’t negotiate his way out a wet paper-bag”, anti-fiscal treaty campaigner Declan Ganley has said.
The head of the Libertas think-tank said Mr Kenny "ran away" from debates on the treaty in the broadcast media.
He told a news conference: "We need to provide some backbone to this government by sending a message to the people that they're sitting across the table from".
Other European leaders might regard the Taoiseach and his colleagues as "soft touches", but Mr Ganley added: "They will know that we're behind them and we cannot be rolled."
Asked if he would make a further attempt to get elected to the European Parliament in 2014, he said: "I wouldn't rule it out. I certainly wouldn't rule it out."
He said he wasn't making any promises, but he added: "What I can promise you is that we need to vote No on Thursday."
Greek-Irish businesswoman Patricia Tsouros told the Dublin news conference she had "no political agenda" but she believed people should "give themselves some time".
The electorate should oppose the treaty on this occasion and she expressed confidence that there would be a second opportunity to vote on it, if it were defeated.
"Let's see what happens with Spain, let's see what happens with Greece," she said.
Expressing cautious optimism that the treaty could be defeated, Mr Ganley said: "I think there is going to be a No vote. It's too hard to call."
He had just done a radio debate on Galway Bay FM where 150 listeners phoned-in to say how they were going to vote, "and it was 53 per cent who were going to vote No".
Part of the reason he expected a high No vote was that people were reacting against the austerity measures: "It's something that is relevant to everybody."
Another reason was that, "Everybody in this country knows that our banks are sort of paralysed and that this bank debt is killing us."
Mr Ganley said the choice facing the electorate was: "Are we going to throw the towel in, are we going to do that in the next 48 hours and just say 'We trust you' to these people that haven't got anything right for the last five years?"
The alternative was to "make a stand" and show that "we have still got dignity in this country".
