The Department of Public Expenditure's top civil servant has yet to say whether he will appear before Wednesday's Oireachtas committee's broadband investigation.
The communications committee requested secretary-general Robert Watt's attendance after he raised serious concerns about the cost of the National Broadband Plan.
Despite written warnings from Mr Watt, the Government decided to press ahead with the planned roll-out of rural broadband to more than 500,000 homes and businesses.
The Cabinet approved a consortium led by Granahan McCourt, as the preferred bidder.
A cross-party investigation into the €5bn plan will also examine the best way to roll out a high-speed network to rural Ireland.
Mr Watt, however, is one of the first witnesses TDs and senators want to question about the project when they gather for a meeting on Wednesday.
However, Mr Watt has so far not responded to the invite.
The communications committee last week agreed to carry out the inquiry into the Government's broadband plan which will take six weeks.
It will then take another two weeks to write up a report which will include identifying the best options to roll out broadband to rural areas.
Fianna Fáil's Timmy Dooley said he wants more analysis of Granahan McCourt's limited €220m equity investment in the plan as against the taxpayers' contribution of €3bn.