The Garda watchdog has been accused of spending €400,000 in a futile bid to find the source of a media leak.

The Sunday Times says the money was spent looking for the source after an article in the same paper in February 2014 claimed GSOC thought it was being spied on.

The report today says the Garda Siochana Ombudsman Commission hired a senior barrister and an IT security firm to comb through phones and computers used by GSOC staff.

Details of the expenses are said to have been sent in a memo to the Public Accounts Committee (PAC) last week.

Renua's spokesperson on Justice, Billy Timmins, has branded the investigation 'an attempt to restrict investigative journalism', adding it's a "real case of Big Brother".