The High Court has granted leave to challenge the constitutionality of the procedures at the Workplace Relations Commission to determine employment rights disputes.
The action could have significant implications for the WRC, which was established in October 2015.
It replaced the previous Employment Appeals Tribunal system of adjudicating claims for unfair dismissal and payment of wages cases.
The case was taken by lawyers on behalf of Tomasz Zalewski, who claims he was unfairly dismissed last December by Buywise Discount Store Ltd, where he was employed as a security guard and store supervisor.
He claims that the WRC adjudication officer upheld the dismissal without affording him fair procedures and constitutional justice.
Mr Justice Seamus Noonan granted Mr Zalewski leave to judicially review the adjudication officer's decision.
He also ruled that the WRC was restrained from progressing Mr Zalewski's appeal to the Labour Court until there is a further order from the court.
The court was told that Mr Zalewski's hearing was "extremely brief", lasting around ten minutes.
The adjudication officer accepted written submissions from both sides, but Mr Zalewski was given no opportunity to cross-examine.