Demands for redress by mica homeowners were described as "off the scale" and giving rise to "very serious concerns" by senior civil servants last month in internal correspondence.

In an email exchange released to RTÉ News under Freedom of Information, officials raised issues about the costs proposed by the property owners and the implications for the State.

Last month, it emerged that the Department of Housing estimated the cost of redress for homes affected by mica as requested by property owners in Donegal and Mayo could reach €3.2bn.

One senior official from the Department of Housing described a meeting which took place with the mica homeowners last month as being "difficult as they have all been".

The official was asked if the Department of Housing had estimated for the cost of mica redress for next year or subsequent years.

In response the civil servant said: "The homeowner representatives presented a final position which we are working on to try and cost but their ask in money terms would be off the scale."

Officials also discussed the possibility of including the defective concrete block grant scheme in the National Development Plan.

A civil servant from the Department of Public Expenditure and Reform commented: "I think we can agree that the ask [from homeowners] and what's potentially available will not be easily reconcilable but at the end of the day there is only a certain amount of NDP funding available."

Prior to one meeting a Department of Housing official said civil servants had asked for the homeowners to provide their final position.

"They refuse to send us a copy in advance which is unusual behaviour," the official added.

Officials also raise concerns about the responsibility for the mica redress being shifted "onto the State" and said advice from the Attorney General on the homeowners' submission regarding redress gave rise to "very serious concerns".

The civil servants warned the development would move the department away from providing a "humanitarian response to help homeowners remediate their homes" to the provision of "a grant scheme … and compensation".

In separate correspondence, Minister for Housing Darragh O'Brien wrote to Minister for Finance Paschal Donohoe last February about banks providing lending to help people repair their homes.

Minister O'Brien wrote: "Financial support or lending for the scheme will be required by some homeowners in order to bridge the gap between the capped grant at 90% of the costs and the full costs of remediation works."

He added that the Mica Action Group said that Donegal homeowners were finding it difficult to get a commitment of support from banks to help them bridge the funding gap.

Minister O'Brien said there has been no policy direction to local branches from senior management and added: "I would appreciate if your Department could be of some assistance in regard to this issue."

However, Minister Donohoe responded that he does not have any role in relation to "the commercial decisions" of banks.

He added: "It will be a commercial matter for the lender to decide whether or not to provide additional credit in any particular case."