Garda Commissioner Nóirín O'Sullivan has one week to come up with a reasonable explanation for the latest crises facing the force or Fianna Fáil will express no confidence in her leadership.
Such a move would almost certainly herald the end of her career and create massive instability for the minority Government.
The deadline comes after it emerged almost 15,000 people are to have their penalty points quashed and that almost one million roadside breath tests recorded by gardaí never actually took place.
Tánaiste Frances Fitzgerald last night expressed "very serious concerns" about the two blunders but indicated that she retains confidence in the Commissioner.
"The scale of the issues which were the substance of a press conference from An Garda Síochána is very concerning," Ms Fitzgerald said.
She noted Garda first highlighted the penalty point issue in June last year by writing to the Department of Justice to indicate it was conducting a nationwide audit. As a result of this audit a further report was provided to the department on March 14, 2017, and the final figures were presented by An Garda Síochána at its press conference yesterday.
Fianna Fáil is set to ramp up the pressure on Ms O'Sullivan, with justice spokesman Jim O'Callaghan telling the Irish Independent the public need "a full explanation in respect of both issues".
He criticised Garda management for holding a press conference to reveal basic details on the scandals but then retreating without providing a full explanation. Ms O'Sullivan chose not to attend the media briefing, which coincided with one of the busiest news days of the year following the death of Martin McGuinness and the terrorist attack in London.
Asked how much time Ms O'Sullivan should be given to provide answers to the outstanding questions, Mr Callaghan said: "I would say they should have answers within a week. If an adequate explanation isn't provided, then we won't have confidence in the Garda Commissioner."
Ms O'Sullivan is already under pressure from other political parties to step aside while the tribunal into the treatment of whistleblower Maurice McCabe hears evidence.
However, a spokesperson for the Commissioner said there was nothing further to add to what is in the public domain "at this stage".
Gardaí revealed on Thursday that 14,700 people were wrongly brought to court without a fixed-charge notice being issued first. They will have their penalty points quashed and fines repaid. The State will have to cover the cost of the process, potentially running into millions.