Two TDs are to take their challenges over super junior ministers attending Cabinet meetings to the Supreme Court.
Sinn Féin Kerry TD Pa Daly and People Before Profit Dublin South West TD Paul Murphy claim only Government ministers can attend Cabinet meetings and the attendance of others breached Cabinet confidentiality.
In December, the High Court dismissed their challenges, ruling that there was no breach of the Constitution.
Mr Daly and Mr Murphy took separate cases dealing with the same issue.
However, both men have been granted leave to appeal to the Supreme Court.
"This is not about those currently serving as Super Junior Ministers. It is about the constitutionality of their role at Cabinet, which the Supreme Court will now determine," said Mr Daly.
"I now look forward to the case proceeding before the highest court, where legal clarity will be established in the public interest."
It is understood the case could be heard later this year.
"The Constitution is very clear in outlining that the Government shall 'not have more than fifteen members' and that it is bound to function collectively and confidentially.
"It seems to me that this is clearly breached by the existence of these ‘super juniors’ who are not constitutionally ministers but act as if they were," said Deputy Murphy.
"I look forward to the Supreme Court making a final ruling," he added.
Both TDs are critical of the composition of the Coalition, with Fianna Fáil and Fine Gael agreeing a Programme for Government in early 2025 with a group of Regional Independent TDs, who were led into negotiations by Tipperary North TD Michael Lowry.
Ministers are appointed by the President to sit as the country's Government.
The Taoiseach appoints ministers of state - and they can be nominated by Cabinet.
There are currently 15 senior ministers at cabinet level, but ministers of state can be selected to attend weekly government meetings - a practice commonplace since the early 2000s.
