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 to Newstalk 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 27th, 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.
Meanwhile, the Seanad mostly now sits in the Dáil chamber in Leinster House - but initially sat in the Convention Centre.
The total cost of Dáil and Seanad sitting in the centre was €499,476, up to the summer recess at the end of July.
The Convention Centre isn't charging for the use of the centre, and the costs mainly relate to staffing and broadcast technology.
Senator Eugene Murphy claims it was not money well spent.
He said: "It's a huge waste of money - remember with the crisis in the economy now over COVID, every penny is going to be important.
"You will find many Oireachtas people in the Dáil and Seanad are extremely annoyed over this."
Rise TD Paul Murphy, meanwhile, said some sittings in the facility are necessary.
He said: "I think it isn't possible for us to follow the NPHET guidelines and do voting or sit every day in Leinster House: that isn't possible, as it isn't big enough for that.
"The services did say they looked at ten different buildings, and the most cost-effective building was the Convention Centre."