Significant inconsistencies have emerged in the Government’s account of how it managed the warnings it received relating to concerns for Air Corps technicians’ health.

The Irish Examiner has learned that, in January 2016, Ms Doherty forwarded a text message onto one of the whistleblowers that she said came from then-Defence Minister Coveney. The message claimed Mr Coveney would call this whistleblower the next day.

Despite their efforts, none of the three whistleblowers have been contacted directly by Mr Coveney or his Department successor, Paul Kehoe, in the year since they made their disclosures.

Last week, Mr Coveney claimed he was “not aware of there being any problem with hearing from, or talking to, or understanding the concerns that whistleblowers may have”.

This week, he repeatedly declined to respond to queries relating to his contact with Ms Doherty on the matter. The revelation is likely to increase pressure on the Government to explain its handling of the affair, which the Opposition described as a scandal the Government tried to bury.

The Irish Examiner recently revealed that the Health and Safety Authority threatened to prosecute the air corps unless it introduced a number of improvements in how it manages its employees’ exposure to cancer-causing chemicals, almost a year after Mr Coveney had received protected disclosures warning him of the working conditions at Casement Aerodrome.

The series of text messages seen by this newspaper reveal that between December 2015 and March 2016, a whistleblower repeatedly contacted Ms Doherty seeking to confirm that Mr Coveney had read his protected disclosure, and to complain that he had no contact from him.

A spokesperson for Mr Coveney said he had received legal advice “not to make himself available to meet with” the whistleblowers, but would not respond to queries as to how he could be unaware of their requests to speak with him in light of Ms Doherty’s text messages.

Ms Doherty said that she was not at liberty to discuss conversations she has had with constituents without their permission. It is understood that Ms Doherty subsequently spoke with the whistleblower in question, who granted her permission to answer queries about their correspondences.

However, Ms Doherty said: “Data protection provisions ensure privacy for constituents in their communications with me and I am not willing to breach that.”