A No vote in the upcoming fiscal treaty referendum would "fatally undermine" the Government and shorten its lifetime, the United Left Alliance (ULA) conference in Dublin has heard.
The ULA is a group of small party and Independent politicians.
Socialist Party MEP Paul Murphy said the referendum provided the ULA with a big opportunity to advocate a "radical alternative".
Mr Murphy said the ULA would not have the field to themselves, and would have competition on the No side from Sinn Féin.
However, he said there was potential to win a "big prize" in the referendum. A No vote would give a "massive boost" to people opposing water and housing charges.
"It would fatally undermine this Government and shorten the lifetime of this Government," he told some 300 delegates this morning.
People Before Profit TD Richard Boyd Barrett said unscrupulous employers thought it was acceptable to "throw workers on the scrap heap" and were refusing to pay the workers what they were owed.
Delegates highlighted the mortgage crisis, while others demanded that trade unions should not adopt a "neutral" stance on the referendum.
Others insisted the ULA should never consider coalition with "capitalist" parties.
