Mr Daly, a solicitor who served as his party’s justice spokesperson from 2020 until this year, is seeking a declaration that the appointment by the Taoiseach of junior ministers with the right to attend Cabinet meetings is unconstitutional.

He is backed by his party in the action against the Taoiseach, the government, Ireland and the attorney general.

Mr Daly said: “I want to thank the judge for hearing my application so quickly and for granting leave for this legal case against the government to proceed.

“For some time now, Fianna Fáil and Fine Gael have been appointing increasing numbers of super junior ministers who attend government meetings as a result of government formation deals.

“They have increased the Cabinet to 19 by the backdoor when the Constitution clearly states it can’t exceed 15 and they have made clear they are treated as full ministers with advisors and powers to bring forward proposals.

“The case will be back in court next Tuesday and I hope that there will be a full hearing as quickly as possible and that there is legal clarity on the matter once and for all.”

Mr Daly is being represented by Feichín McDonagh SC, Brendan Hennessy BL and John Biggins BL, instructed by solicitor John Rogers.

Sinn Féin leader Mary Lou McDonald previously said the appointment of the super junior ministers “smacks of arrogance and entitlement by those who believe that the rules don’t apply to them”.