The Garda Commissioner is due to tell the Oireachtas Joint Committee on Justice and Equality her real fear is that the falsification of data is not confined to traffic.

Nóirín O'Sullivan's speech, which she is due to deliver when she appears before the committee at 9am tomorrow, was circulated to members of the committee this afternoon.

Her appearance before the committee comes as the force comes under heavy criticism for serious irregularities in road traffic policing.

Last week it emerged that more than 14,500 people who were prosecuted for road traffic offences are to have their convictions quashed as a result of a controversy over fixed charge notices and the exaggeration of garda breathalyser test figures.

It was revealed that from 2011 to 2016 the number of drink-driving tests gardaí claimed to have carried out was hugely exaggerated, by over 937,000.

A copy of Ms O'Sullivan's speech, which has been seen by RTÉ News, states that some gardaí recorded numbers that were false.

It says that at worst this was deception, at best it was incompetence.

Ms O'Sullivan states in the speech that either way, it was individually and organisationally shameful.

She adds that it will be seen to be shameful by the public and the thousands of gardaí around the country who operate every day to the highest ethical standards.

Ms O'Sullivan also says the discovery raises serious questions of supervision and management.

The commissioner adds that she will ensure the people responsible at all levels will be held to account.

Separately, Ms O'Sullivan has also been called before the Dáil's Public Accounts Committee to explain financial irregularities at An Garda Síochána's training college at Templemore in Co Tipperary.