It cost almost €500,000 to hold Dáil and Seanad sittings in the Convention Centre in just one month.
The new figures have been released under the Freedom of Information Act.
For social distancing reasons, several sittings of the Dáil and Seanad have taken place in the Convention Centre.
The first was held on June 27, when TDs met to elect Micheál Martin as the Taoiseach.
The Dáil continues to sit in the centre when all members need to be present to vote.
The Seanad mostly sits in the Dáil Chamber in Leinster House but initially sat in the Convention Centre.
The total cost of Dáil and Seanad sittings in the centre was €499,476 up to the summer recess at the end of July.
Rise TD Paul Murphy says some sittings in the facility are necessary.
"I think it isn't possible for us to follow the NPHET guidelines and do voting for us to sit every day in Leinster House.
"That isn't possible, it isn't big enough for that.
"The services did say that they looked at, I think, ten different buildings and the most cost effective building was the Convention Centre."
The Convention Centre is not charging for the use of the centre, and the costs mainly relate to staffing and broadcast technology.
Fianna Fáil senator Eugene Murphy claims taxpayers' money has been wasted by holding Oireachtas sittings in the Convention Centre.
"Remember with the crisis in the economy now over Covid, every penny is going to be important.
"You will find that many Oireachtas people in the Dáil and Seanad are extremely annoyed over this and would prefer to see us getting back to Leinster House and do all of our business there both in the Seanad and in the Dáil."