Officials at the Department's policing division provided the advice to the Minister, in January 2017, despite GSOC having told the Department that it would be unable to meet its objectives in relation to the complex issue of protected disclosures coming from members of An Garda Síochána, without the extra resources they were looking for.
The previously unpublished briefing note was obtained by RTÉ's This Week radio programme under a Freedom of Information request.
GSOC had made a request some weeks earlier for 12 extra staff, as part of a detailed business case for the establishment of a dedicated protected disclosures unit.
The Commission told the Department they needed the extra personnel and other resources to deal with a growing number of such disclosures from members of the force.
Some months later, in May 2017, GSOC was ultimately given permission by the Department of Public Expenditure and Reform, which overseas public spending, to hire just five of the 12 staff they asked for.
The Chairperson of GSOC, Ms Justice Mary Ellen Ring later described this allocation of staff as "insufficient" and disappointing, in a letter to Minister Fitzgerald that same month.
However, according to previously unpublished documents, it has now emerged that officials at the Department of Justice had formed an early impression just weeks after the request was made, that GSOC's demand was in excess of what they needed.
This comment in contained in the January 2017 briefing note from the Department to then Minister Fitzgerald, prior to a meeting she had with the Ombudsman Commission.
The letter clearly says that GSOC's business case and the matter generally would be discussed with GSOC. However, a spokesman for the Commission told RTÉ's This Week programme that they were never informed by the Department that they had formed the view that the request was excessive.
The Department of Justice told RTÉ News that it formed an initial view early on that the request was excessive, on the basis of the number of disclosures made to GSOC up to that point in time, in early 2017.
At that time, around ten disclosures had been made since GSOC was designated as the recipient for disclosures from the force. However, since then, the number of such disclosures has in fact doubled to twenty, GSOC recently revealed.
In related correspondence, the Department of Public Expenditure and Reform wrote to the Dept of Justice on 5 May, and made specific reference to the decision of the Department of Public Expenditure and Reform to sanction the release of public funds to allow GSOC to hire some of the extra staff they requested.
In that 5 May letter, the department wrote to Justice telling them it had sanctioned five extra staff for GSOC "as requested".
Neither the Department of Justice nor the Department of Public Expenditure and Reform responded to a query by RTÉ News about whether this indicated that the Department of Justice had sought approval for the hiring of less staff than GSOC had signaled they needed.
Correspondence also shows that GSOC had said they wanted to deal directly on the matter with the Department of Public Expenditure and Reform but for some reason a meeting did not take place, and the Department of Justice remained the sole conduit for GSOC's resourcing request.
Responding to a series of questions from RTÉ News, the Department said GSOC had submitted a business proposal to the Department for the creation of a designated unit to handle protected disclosures, around 14 months ago.
"The Chairperson stated that the formation of the separate unit would instill confidence in members of An Garda Síochána to come forward with further information. The proposal requested funding for a secure and separate office within GSOC with an additional 12 new staff", the Department said.
"Policing Division prepared a briefing document for the then Minister's meeting with GSOC on 11 January 2017. That briefing document made reference to GSOC's business proposal for a Protected Disclosure Unit stating that it was under review and that Policing Division's first impressions were that it would appear somewhat excessive," the Department confirmed.
The statement noted that there were, what the Department described as "a relatively small number of protected disclosures on hand in GSOC" around the time that GSOC made the business case for a dedicated unit.
"It must also be borne in mind that GSOC themselves had admitted that it was difficult to estimate the staffing requirement for their new Unit," the Department said.
The Department confirmed that GSOC indicated their preference for a meeting with the Department and the Department of Public Expenditure and Reform "so that the workload and complexities involved with protected disclosures cases could be best explained. Their request for a meeting was relayed to the Department of Public Expenditure and Reform who responded indicating that they would wish to see the information requested in advance of any such meeting".
"Subsequently DPER made a decision to sanction the 5 staff but only on the basis that they were provided, within 3 months, with specific information regarding staffing ratios for current caseloads, typical staffing requirements per case, per type of case, etc. In the absence of the detailed analysis that DPER had requested, it was difficult to justify the level of resources that were being requested at that time. That said, there was a clear commitment on the part of the Department that GSOC could re-engage on the issue as the situation developed and that the door was open to more resources being made available if the evidence supported it," the Department said in their statement.