The most senior official in the Department of Communication will be before the Public Accounts Committee later today to answer questions on the National Broadband Plan.
Secretary General Mark Griffin will be grilled by TD's and Senators on procurement and costings of the project.
Original estimates put it at between 355 million and 512 million euro, however recently Taoiseach Leo Varadkar admitted it will be "many multiples" of what was budgeted.
Chairman of PAC, Fianna Fail TD Sean Fleming, says members will want to know everything is in order given the huge costs involved:
"I'm not satisfied that it is future proof yet and that is what we need to hear from the Secretary General today," he said.
"No doubt he'll say it's future proof but the Public Accounts Committee will want to know (that) this tender process that has been going on for a number of years now is up to scratch and fit for purpose because there is a major cost to the exchequer involved here."