The European Court of Justice will hear arguments today surrounding objections by Independent TD Thomas Pringle to the ratification of the European Stability Mechanism (ESM) treaty.
The Government initiated ratification of the ESM in August following a refusal by the Supreme Court to grant Mr Pringle an injunction to halt the process before the European court had time to rule on its lawfulness.
Mr Pringle argued that, by adopting the treaty, Ireland would undertake obligations which would contravene provisions of the EU treaties concerning economic and monetary policy and would directly encroach on the exclusive competences of the EU in the matter of the euro and related policies.
Mr Pringle told RTÉ's Morning Ireland he believed the ESM sets up "an institution that isn't accountable to any of the European institutions and it's providing for euro zone member states to join that facility in order, I believe, to circumvent the no-bailout clause within the European treaties".
He added: "If the court agreed fully with my arguments, member states who are already members of the stability mechanism would have to withdraw because it wouldn't be compatible with the union.
"It would require that the European council would go back and implement a stability mechanism that is compatible with being a member of the European Union."
In July the seven-judge Supreme Court ruled that if the court of justice ultimately upheld Mr Pringle's claims, that will be an adequate remedy.
The European Court sought written submissions from Mr Pringle and the State's legal representatives ahead of today's scheduled oral hearing. The court fast-tracked the one-day hearing, meaning a judgment is expected by the end of the year.