The cost for the recently completed Stardust inquests is set to amount to more than €20m, with legal fees making up over half the total.
The figures, released from the Department of Justice, also show that €4.5m was spent on rent.
The overall bill is more than twice as much as the €8m that was allocated for the inquests in budget 2021.
The €20m covers the three-year lead-in period to the proceedings when preparatory work was being carried out, as well as the year-long hearings which were held in public.
The inquests, which sat for 122 days and heard from hundreds of witnesses, concluded last April, with the jury returning a verdict of unlawful killing.
48 people died when a fire tore through the Artane night club in the early hours of 14 February 1981.
Families had campaigned for many years for the fresh inquests to be held.
According to the Department of Justice, €13.6m was spent on legal fees, with each family represented in court and receiving legal aid.
The figures also show more than €1.5m was spent on reports from medical and fire experts.
The bill for 'miscellaneous' expenses, including stenography, audio and visual services, catering and witness expenses amounted to €612,000.
It comes as a redress scheme for relatives and survivors has yet to be finalised.
Earlier this week, families of the victims, said they had been told by Minister for Justice Helen McEntee that the Government was "still working on" it.
The inquests, which began its public hearings in April 2023, were held in the Pillar Room on the grounds of the Rotunda Hospital, and not in the regular coroner's court, to allow for more space.
The department said salaries for its staff who were assigned to assist the coroner were not charged to the Stardust budget.
