The 80-page report, to be published today, is expected to vindicate the Garda whistleblowers.

It will bring into sharp focus the handling of the penalty points controversy by Mr Shatter since the publication of an internal Garda report on the issue last May, including his criticism of the actions of those who raised concerns.

Mr Shatter last night conceded the report would highlight “major administrative dysfunction” in the system and a “failure of management oversight”.

Sources close to senior Government ministers said the report, which will also be discussed by Cabinet today, would be “damning” about actions in the force.

One of the whistleblowers, John Wilson, said the report’s findings “call into question” the internal Garda report by Assistant Commissioner John O’Mahoney, which he said “minimised the allegations” he and Mr McCabe made.

That report was declared a “whitewash” by the opposition at the time, and Mr Shatter asked the Garda Inspectorate to review the penalty points system as well as the original O’Mahoney report.

The Garda Inspectorate spent eight months looking at the system and its chief inspector, Robert Olson, also interviewed Sgt McCabe about gardaí quashing penalty points.

Mr Shatter said that following the inspectorate’s report, there was a “comprehensive road map” to ensure the total integrity of the fixed-ticket charge system.

He said: “There is a major administrative dysfunction, a failure of management oversight and these are all issues that we need to ensure are addressed, that there’s full transparency to the system and that there’s no doubt about its integrity.”

The inspectorate’s report is expected to recommend the cancellation of points be taken out of the hands of superintendents and instead be dealt with by a central unit.

It also highlights concerns about the processing of points, the lack of record keeping regarding fixed charges and the wiping of points.

It will also highlight where changes are needed on how points are allocated to the drivers of company or hired cars, where payments are being made instead of cases going to court and issues around the endorsement of points on licences.

A Department of Transport spokesman last night said these changes are already legislated for but “cannot be enacted because the gardaí and courts have yet to agree to implement them”.

Fianna Fáil criticised what it described as the minister’s “selective leaking” of details of the report, which was reported on RTÉ’s Six One news yesterday evening.

Party justice spokesman Niall Collins said: “Once again, on an important issue of public order, Alan Shatter and the Government’s first priority is news management and trying to maintain control of headlines.”

Independent TD Mick Wallace told RTÉ’s Prime Time the minister and Garda Commissioner Martin Callinan had “gone to huge lengths to minimise everything that came their way”.