The head of the Department of Health is to appear before the Public Accounts Committee over Tony Holohan's secondment.
The chief medical officer's due to become a professor at Trinity College - but the government has paused the appointment.
Ministers are concerned about the recruitment process, and how the state will continue to pay his wages.
PAC chairman Brian Stanley says the secretary-general of the department, Robert Watt, has questions to answer:
"I certainly will be proposing to members of the Public Accounts Committee that he'd be brought before the Public Accounts Committee to outline the process here. Who decided that Tony Holohan could move over to Trinity College, a third-level institution with separate funding, (some private, some public) to a position that is paid in excess of what the other professors at that college are paid and who decided that the taxpayer would pay his wages?"
