The Taoiseach has said he would "absolutely welcome" an examination of the National Broadband Plan by the Oireachtas Committee on Communications, Climate Action and Environment.

Yesterday Fianna Fáil proposed that the committee initiates an investigation into the bidding process behind the plan.

Leo Varadkar told the Dáil he would have "no objection" to such an inquiry.

However he said there needs to be a "reasonable timeframe around it and that the terms of reference are agreed by the major parties."

The Taoiseach also told the Dáil that there will be a budgetary impact from the plan from 2021 onwards.

He said the Minister for Finance, Paschal Donohoe, will indicate in the Summer Economic Statement due in a couple of weeks time how that funding will be provided for.

He said there will be no budgetary impact in 2019 and a minimal budgetary impact on 2020.

He was responding to the Fianna Fáil leader, Micheál Martin, who asked where the additional funding will come from.

"You declared it to be an expensive and ambitious plan. But I would remind you it is not your money, it is the taxpayer's money. And you are electioneering and playing politics with large sums of taxpayers’ money," Mr Martin said during Leaders' Questions.

Mr Martin said that if the contract is signed €500 million has to be found between 2019 and 2022.

"Over €1.5 billion has to be found now from the National Development Plan - over and above the €800m already allocated for the plan," he said.

"This is on top of additional funding that will be required of €385m for the National Children's Hospital over the next three years. There is no provision anywhere for this funding that we can see, despite asking very basic question about where this funding will come from."

The Minister for Communications has said there are "fundamental constraints" in terms of changing aspects of the broadband contract.

Richard Bruton was responding to Green Party leader Eamon Ryan, who asked if there was a window to change the contract before it is closed.

"Clearly you cannot re-write the competition rules. We have had a competition. We defined certain terms of the competition from the outset... so there are fundamental constraints on what alternatives you can look at without starting afresh and abandoning this tender, and starting a new procurement process," the minister said.

Mr Ryan also said he wanted to support the broadband plan, but was scratching his head around the ownership.

"How can we have a private developer contributing €175m in capital and we're contributing between €2 and €3bn and they end up owning the asset. I think the Irish people are scratching their heads on this too and can't get around what do we get from that?" Mr Ryan said.

Mr Bruton said they had evaluated every alternative and all of the alternatives are either more expensive, more risky or would not deliver.