Minister of State Patrick O'Donovan has dismissed suggestions that he should take a polygraph test, following allegations that he was behind a sting operation to identify an individual who was leaking from Cabinet.

Minister O'Donovan told Limerick's Live 95 that the proposal from Senator Rónán Mullen that both he and the Minister for Further and Higher Education, Simon Harris, should undergo a polygraph test was not a reasonable one.

He said it was not a suggestion that could be taken seriously in a modern parliament.

Asked if he had been boasting to Fine Gael colleagues about the alleged sting operation, Mr O'Donovan said he never comments on discussions with fellow members of the parliamentary party.

Last week, Sinn Féin TD Matt Carthy used Dáil privilege to accuse Minister Harris of leaking from Cabinet, a claim Minister Harris strongly denies.

Mr O'Donovan, the Minister of State with responsibility for the Office of Public Works, accepted that the controversy over the appointment of Katherine Zappone as a UN Special Envoy was not handled properly.

He said lessons have been learned, however, he said he was now focused on the work of Government.

Separately, Mr O'Donovan said he believes that addressing the problems caused by mica and pyrite could be the biggest challenge the Government will face.

He expressed concern that the issue will spread to many other counties and said that some homeowners are not even aware that their houses are affected.

It could prove more challenging for the Government than the pandemic, he said.

He added: "Let nobody be under any illusion. This is enormous."

Minister O'Donovan said that Government had to "walk a line" with regards to addressing the issue, while also managing the potential costs associated with it.