Eurozone neighbours are pressing Ireland to raise the 12.5% corporation tax rate as part of negotiations for a rescue package but Dublin is resisting, arguing that it is crucial for foreign investment.
Irish Deputy Prime Minister Mary Coughlan told parliament the corporate tax rate was "non-negotiable".
European Minister Dick Roche echoed that comment, saying "it is certainly not up for negotiation".
"There has been some very unhelpful chatter in the background in the last few days about our corporation profit tax. Where would be the sense of destroying one of the great drivers of growth?" he told BBC television.
Britain and Germany have long viewed low Irish taxes as a form of unfair competition and the finance ministers of Austria and France said the corporation tax may have to be raised as part of any deal.
Michael Meister, a deputy leader in parliament and finance expert for Angela Merkel's Christian Democrats (CDU), said the country needed to consider raising the levy.
"The Irish rates are below the European Union average," Meister told Reuters on the sidelines of the CDU annual party congress on Tuesday (16 November). "I therefore see here at least a possibility, given the high [Irish] budget deficit, to improve revenues without causing a negative impact on growth," he added.
Meister's comments come one day after Elmar Brok, a senior CDU lawmaker who has sat in the European Parliament since 1980, said Ireland may have no choice but to raise the rate. "Ireland has two options to consolidate its budget – cut expenses even further or increase taxes like the corporate tax rate," Brok said at the congress in Karlsruhe.