A Fianna Fáil TD has said the party has been given "solemn assurances" that all documents are with the Disclosures Tribunal following the controversy over emails concerning a garda whistleblower that led to the Tánaiste's resignation.

Dara Calleary said Minister for Justice Charlie Flanagan has given a guarantee that at this stage everything possible has been done.

He said he hoped there would now be "a vigilance" within the Department of Justice.

Taoiseach Leo Varadkar has said that an external inquiry into the workings of the department will be completed before Christmas.

Yesterday, Mr Flanagan told the Dáil that he "simply missed the significance" of a May 2015 email about the treatment of Sergeant Maurice McCabe at the O'Higgins Commission.

Further correspondence released this week by the department following a trawl of its records showed that former tánaiste Frances Fitzgerald was aware of the "aggressive stance" against Sgt McCabe at the commission, which effectively signalled her resignation from Government.

Speaking on RTÉ's Morning Ireland, Deputy Calleary said Fianna Fáil has been "given guarantees that the search and the trawl [of the department] was as comprehensive as possible".

He said that "two ministers (Alan Shatter and Frances Fitzgerald) have resigned because of the position of the Department of Justice and we always move onto the next minister while the department stays the same.

"It's time for us to actually have a look at the ship instead of consistently focusing on the crew and the ship needs a complete re-design and needs to be made fit for modern practice".

He added that "in fairness to Charlie Flanagan last night, he showed and he demonstrated an awareness of the seriousness of this situation in a way that Frances Fitzgerald never did".

Documents released by Department of Justice
Email chain regarding stance at O’Higgins Commission
Final report to Secretary General Noel Waters
Report to the Taoiseach 24 November 2017
Recommendations of the Toland Report
Letter from Disclosures Tribunal

Speaking on the same programme, Social Democrats co-leader Roisin Shortall said she does not believe that Minister Flanagan can say with authority that documents were not deliberately withheld from the Disclosures Tribunal by the department.

"It is simply unbelievable that if a department was serious about getting to the bottom of this, a basic search, a google search with McCabe or O'Higgins would have produced those emails. 

"It is not credible that if there was any kind of serious search done that they wouldn't have shown up", she said.

Ms Shortall added that given the background to this case, "anything that comes into the Department of Justice relating to Sgt McCabe or O'Higgins should have immediately set off alarm bells."

She said that "a query then in from Charleton, asking for discovery of all documents should have meant down tools, get to the bottom of this.

"There were 11 people on the circulation list for all of these emails. How come those emails didn't turn up in a basic search?"

Sinn Féin has published a private members’ motion to amend the tribunal’s terms of reference.

The party believes that the tribunal should look at why crucial documents were not sent to it by the Department of Justice and to find out if they were deliberately held back from it.

Justice spokesperson Donnchadh Ó Laoghaire said there may need to be another module to look at this issue and at the specific knowledge that civil servants had of the legal strategy of former garda commissioner Nóirín O’Sullivan.

The Disclosures Tribunal, chaired by Mr Justice Peter Charleton, was established to investigate allegations that there was an organised campaign against whistleblowers at the highest levels of An Garda Síochána.