The National Broadband Plan's tendering process was not fit for purpose, according to Fianna Fáil.
Officials from the Department of Communications will face questions from an Oireachtas committee this evening.
Telecoms firm Eir has claimed it can supply rural broadband for €2bn less than the price quoted by the Granahan McCourt consortium.
Fianna Fáil's communications spokesman Timmy Dooley says Eir's proposal has to be considered.
"Eir have indicated that they can deliver high-speed broadband throughout the vast track of rural Ireland for €2bn less than the proposed company that the government have identified," said Mr Dooley.
"That has to be taken seriously and the government must work through that.
Also recognising that Eir has a very considerable track record in this country and has a lot of experience in rolling our high-speed broadband.
Mr Dooley, who sits on the Communications Committee, said that the tendering process was clearly flawed.
"The government on behalf of the State has advanced with a procurement process that is not fit for purpose because it ends at a situation where a company with no track record, with no real base in Ireland, with no know-how in this regard is going to charge €3bn to do something that a company of the size and scale and experience of Eir say they can do for €1bn.
"There's something wrong there."