Garda Commissioner Nóirín O’Sullivan has indicated she will not stand down, even if the Dáil votes no confidence in her next week.

At a press conference in Garda Headquarters in the Phoenix Park on Monday evening, Ms O’Sullivan said she was determined to see through the reform of An Garda Síochána that has been in train since she took up her role in an acting capacity in 2014.

Ms O’Sullivan has said the force had heard the “disquiet” about the controversy over the recording of one million breath tests that never took place.

Ms O’Sullivan said the issues had been identified with the fixed charge penalty system a number of years ago.

“It is gives us no comfort to say we identified these issues,” she said. “We have heard very, very carefully . . . the disquiet around the issues.”

She said there would be a “radical restructuring” of roads policing, adding: “This is a matter of real cultural reform.”

“I have a journey of work that I have to do and I have to make sure I see through that commitment,” she said. A review into the controversy, she said, should produce initial results within three months.

“We have to get to the bottom of where this problem is,” she said, adding that goes all the way down the organisational structure of An Garda Síochána. “Who has done what and what has been done. We have to get to the bottom of this.”

One of the factors to be addressed is why this issue never came to light before.

She said An Garda Síochána was on a “huge journey” of radical reform. She said the public disclosure last week by An Garda Síochána of the huge discrepancies in the fixed charge system came because of the scale of the problem. Ordinarily, such a disclosure would not be made, she said.

Ms O’Sullivan said if it was found that, in any case, “there is a deliberate falsification of facts”, the appropriate action would be taken.

“There is no doubt this is a very, very serious issue,” she said. “We have potentially very, very serious ethical issues here.”

She said An Garda Síochána have to “get to the bottom” of what happened, and did not reply when asked if investigations into the discrepancies in the system are criminal. She said it was about “fact finding”.

“What we have to do is satisfy ourselves what precisely happened,” Ms O’Sullivan said. “We are absolutely committed and determined to addressing the issues.”

Also at the press conference, Deputy Commissioner John Twomey said of the inflation of the figures: “It is unethical and it will not be tolerated.”

Mr Twomey said the action that had been taken since the discrepancies had been discovered showed the seriousness with which the issue was being considered. He said any problems that will be identified will be then corrected.

Mr Twomey said the Policing Authority was not informed of the issue in 2016 because of an administrative error on his behalf. He said he regretted this.

A detailed timeline of what and when An Garda Síochána knew about the problems was distributed at the press conference. It said the force first became aware of the issue with roadside breath test figures in April 2014 on foot of anonymous correspondence sent to Road Safety Authority.

The correspondence was passed to An Garda Síochána by then minister for transport Leo Varadkar.

In 2015, a review of road traffic equipment and data from the Pulse system was conducted in the southern administrative region, which found there was a data discrepancy of 17 per cent. A full review of all breath test data began in 2016.

Ms O’Sullivan’s press conference came just hours after a meeting with Tánaiste Frances Fitzgerald in the Department of Justice.

They discussed the fallout from the disclosure that a million breath tests recorded by An Garda Síochána had never taken place.

Political pressure is increasing on Ms O’Sullivan, with Sinn Féin on Monday morning publishing a motion of no confidence in the commissioner. The motion will be taken in the Dáil next week.

Fianna Fáil has called on Ms O’Sullivan to plainly set out the facts of how the issue arose. It says it cannot express confidence in Ms O’Sullivan unless she provides clarity.

Taoiseach Enda Kenny said there was “an opportunity for the commissioner to set out all of the facts”.

Speaking in Tralee on Monday morning, Mr Kenny said: “I do expect that the commissioner will outline for the Minister for Justice the facts, as can be put in the public domain, the facts that are available to her.”

Government sources speculated that the prospects of the Garda Commissioner surviving the week are “50-50” and said Ms O’Sullivan acknowledges there is a need for her to take public responsibility.

It is also expected that the Commissioner will appear before the Oireachtas Justice Committee on Wednesday.

Jonathan O’Brien, Sinn Féin’s justice spokesman, said the Government should use the powers available to it under the Garda Síochána Act of 2005 to remove Ms O’Sullivan from office.

The Cabinet is expected to discuss the controversy on Tuesday.