Fianna Fáil have sought a meeting with the Government to seek an explanation on the rising cost of the National Broadband Plan.
The Government is expected to go against concerns raised and approve the plan in the coming weeks.
It has been reported that senior officials - including Robert Watt, Secretary General of the Department of Public Expenditure and Reform - told Taoiseach Leo Varadkar and Finance Minister Paschal Donohoe that the plan to deliver high-speed broadband to every home and business in the country should be abandoned due to escalating and unaffordable costs.
While the Government initially said it would cost €500m to roll-out rural broadband, that has now increased to €3bn and the one remaining bidder has yet to be approved by Cabinet.
Fianna Fáil's Barry Cowen has written to the Finance Minister demanding that all advice received on the project be published.
"I am anxious to meet with him to discuss this. I don't want to get in the way or to delay the scheme but I have a responsibility and a duty to scrutinise the details and the advice given, this is in the public interest," Fianna Fáil's spokesperson on public expenditure and reform said.
It is understood that Mr Donohoe may now meet Mr Cowen later this week to discuss the advice the Government has received on the plan.
However, a spokesperson for Mr Donohoe claimed: "no request of that nature has been submitted".
She confirmed that the Minister had received the letter from Mr Cowen adding: "Minister Donohoe will respond shortly".
Mr Varadkar had said that a decision on the plan, which was first published in 2012, would be made before Easter. However, this deadline was missed and the NBP will not be discussed when the Cabinet holds its weekly meeting in Cork on Wednesday.
A spokesperson for Communications Minister, Richard Bruton, said the Government wants to deliver broadband to the remaining 540,000 premises in rural Ireland for whom it is clear that commercial operators will not deliver high-speed, future-proofed services.
"However, we have to make sure we do it right," the spokesperson said.