The Department of Finance and the National Treasury Management Agency carry out regular sweeps to ensure they are not subject to any bugging or surveillance.

Minister for Finance Michael Noonan confirmed the steps were taken due to the commercial sensitivity of issues being discussed within the department.

However, other departments declined to reveal if they undertake similar counter-surveillance measures.

In response to parliamentary questions from Fine Gael TDs Brendan Griffin and Noel Harrington, Mr Noonan said he was "aware of the importance of maintaining security given the commercially sensitive meetings held in the department and the sensitive information held by the department".

It is understood the sweeps are carried out by the Garda.

A spokesman for the NTMA said it also carries out sweeps.

“Given the sensitivity of the business activities of the NTMA and its various linked business units, including Nama, the agency carries out regular, comprehensive security checks, including sweeps for any evidence of bugging. ”

The Central Bank would not confirm if it took measures to protect from surveillance. "We don't discuss security issues," a spokeswoman said.

A source said the Department of Transport had been swept in the past, and inquiries have been made about doing so again.

The services to departments are provided by the Garda Síochána.

Bugging equipment
Minister for Public Expenditure Brendan Howlin said "no office in my department has been swept for electronic or any other type of surveillance or bugging equipment", while Minster for Justice Alan Shatter said "for obvious reasons it is not the practice to comment on security-related matters".

Mr Griffin, a Kerry South TD, said sweeps should be "done at all departments and in the Leinster House complex itself".