Sinn Féin's Finance Spokesperson Pearse Doherty has accused Cabinet ministers of taking a "hands off" approach to the National Children's Hospital.

During Leaders' Questions, Deputy Doherty told Minister Eamon Ryan that there was a "complete vacuum" of transparency and accountability in relation to the project, given that no estimated costs were shared with the Oireachtas health committee yesterday.

"It's a never-ending saga of more claims and more claims, rising costs and no completion date in sight," he said.

The estimated date of completion is December 2023, with an estimated opening date in the second half of 2024.

Deputy Doherty said that Tánaiste Leo Varadkar and Minister Simon Harris held the position of health minister at a time when action could have been taken to curb the rising costs, telling the Dáil that the hospital was due to be delivered in 2020 for €650 million, but it is now expected to exceed €1.7 billion.

Minister Eamon Ryan said that the final cost could not be shared with the Dáil as the project is ongoing.

He described the rising costs and other contractual difficulties as "unsatisfactory", telling Deputy Doherty that lessons would have to be learned.

Minister Ryan said there is a wider issue around planning, development, costing, and delivery of major construction projects in this country, and the Children's Hospital is an example of that.

Meanwhile, Social Democrats co-Leader Catherine Murphy accused the Government of "tying itself in knots" to explain its U-turns on housing.

She rejected Taoiseach's Micheál Martin's suggestion, made in the Dáil yesterday, that an exemption to stamp duty for investment funds leasing back to local authorities was signalled in advance.

The revelation that 2,400 lease deals will be signed this year with investment funds, up from 1,440 last year, was "a surprise", she said, and noted that there are additional deals "in the pipeline".

"How many lease deals do we expect in 2021?" she asked. "Do you accept that this is awful value for public money?"

"This is an abuse of public money," Deputy Murphy added.

Taking Leaders' Questions, Minister Ryan told the Dáil that the Housing for All strategy will see a change in leasing arrangements. "We do need to change" the approach, he admitted.

There are 2,450 units in this year's target.

The minister's recollection is that "there was clear indication.. there was a clear signal in that particular category."

Mr Doherty accused the Government of pulling "a political stroke by forcing through a last minute amendment" last night to give a tax break to vulture funds.

"You really couldn't make it up," he said.

In exempting investment funds from stamp duty when they lease back to local authorities, he said the losers are "the ordinary people... aspiring homeowners.. first time buyers... renters... and tax payers".

Speaking during Promised Legislation, Minister Ryan said the Government's intent is to deliver social housing. "I can't accept that kind of definitive split," he said, that one side of the House supports vulture funds, and the other, public housing.

Labour TD Aodhán Ó Ríordáin said that 343 units in a development in Marino, in his constituency, are being sold to a vulture fund, while young people are facing average rents of almost €2,000 a month.

The minister said the way to avoid this happening again is to work with the Land Development Agency and "to actually go into the market", and bring prices down.

"It takes time" for cost-rental to work, but Vienna has shown that it can work, he said.