An effort by the Irish language ombudsman to establish if a district judge could speak fluent Irish was blocked by the Government.
An Coimisineir Teanga, Sean O Cuirreain, launched the investigation after a district judge was appointed to a Gaeltacht area of Donegal.
The 1924 Courts of Justice Act states that a judge allocated to a district where the Irish language is in general use must have enough of a grasp of the language so that an interpreter is not required.
Mr O Cuirreain, who yesterday published his fourth annual report since being appointed the Irish Language Commissioner, said he received a complaint by Conradh na Gaeilge following the appointment of the district judge in Donegal.
The probe was one of the investigations carried out by his office last year following 622 complaints received from the public and organisations.
However, the efforts to establish if the judge could speak Irish was blocked by the Government.
Mr O Cuirreain said that this is the first instance on record where the Government impeded the work of a State ombudsman.
His office provides advice to the public about language rights, and to public bodies about their obligations under the 2003 Official Languages Act. Mr O Cuirreain's office then investigates complaints of alleged breaches of the legislation.
In the case of the judge's appointment in Donegal, Mr O Cuirreain sought a report from the commissioner's office from the Department of Justice, Equality and Law Reform. He also sought access to the relevant files.
However, a certificate was issued by the Secretary-General to the Government covering most of the relevant records.
Such a certificate, under the Official Languages Act, denies access to specified information.
Mr O Cuirreain said that he had to discontinue the investigation as a result.