Updated

Rival campaigners in Ireland's referendum on the European Union fiscal treaty are arguing up to the last minute before voters must decide whether to ratify the eurozone's deficit-fighting plan.

The anti-treaty side received last-minute support Wednesday from news reports suggesting that Ireland's bailed-out banks might need €4 billion ($5 billion) more beyond the €64 billion ($80 billion) already committed, a burden that forced Ireland to seek its own 2010 bailout.

Opponents of the treaty say Ireland should threaten to default on toxic bank debt and demand more forgiving terms from EU partners. Pro-treaty campaigners led by the government insist Ireland can't gamble on its future EU financing and must stick to bank bailouts and deepening austerity.

All recent opinion polls suggest the treaty should be approved in Thursday's referendum.