The Finance Minister says further explanation is needed as to why a €1.37 million Oireachtas printer isn't yet operational.
Re-modelling work of almost €230,000 was needed to install the new printer, which is still not operational.
The works were completed earlier this year, but staff have not yet received the health and safety training needed to operate the machine.
The final costs of the Oireachtas printer works.
€1.37m for printing equipment
€229,000 installation costs
€195,000 other costs for work carried out at same time
— Seán Defoe (@SeanDefoe) November 28, 2019
The union representing workers, SIPTU, said earlier this week that they are 'in discussions with management' on the additional demands and skills which are required to operate the machine.
Speaking on Newstalk Breakfast this morning, Paschal Donohoe said more answers are needed - suggesting the "magnitude of challenge" in relation to the installation of the machine "verges on the inexplicable".
He stressed that the Houses of the Oireachtas are 'completely independent' of Government and are therefore responsible for their own affairs.
However, he observed: "Within that context... two things. The first thing is that the way these costs have developed and the inability of the machine to work clearly requires scrutiny from the Public Accounts Committee - which is going to happen.
"The second thing is, amidst the huge annoyance about the cost, what I think equally needs explanation is why there was not agreement then to make it work.
"What are the work practices that meant that after a significant capital investment like this, it then couldn't be used? That is a separate point which needs to be teased out."
Minister Donohoe acknowledged that challenges do happen during large equipment purchases or other major projects.
However, he added: "The magnitude of challenge in relation to this verges on the inexplicable in relation to the machine and the space it had to go into.
"What should be equally of concern is what is the particular work practice and issue that meant it couldn't be used?
"We have made great progress in dealing with these issues in recent years across many parts of our public service, with cooperation and engagement through unions and so on. That is why this is of particular concern."