Senior Gardaí have privately hit out at claims by a member of the independent Policing Authority that Garda Commissioner Nóirín O’Sullivan has faced “internal challenges” due to “difficulties with her own team”.

The claims were made by former PSNI deputy chief constable Judith Gillespie, who called for Ms O’Sullivan to be given the time to “turn the organisation around”.

Ms Gillespie said in an interview that she has “known Ms O’Sullivan for many years” and that she deserves a “fair chance” to transform the force.

“I think Nóirín is an incredibly resilient person. I have known her for many years. I think she has had a very difficult job to take over with the history of the organisation. I do think she has had difficulties with her own team as well and that has posed internal challenges as well as external challenges she has had to face,” Ms Gillespie said.

“I think she has to be given time to turn the organisation around. You are never going to be able to make these cultural changes overnight. It is going to take time,” said Ms Gillespie.

In the interview with the Press Association, Ms Gillespie added that the Policing Authority, which she joined in January 2016, will be watching her performance very closely.

“There will soon be a time when we expect to see tangible evidence of changes delivered, and the [Policing] Authority is watching very closely in terms of the implementation of the Garda Inspectorate report.”

However, the Irish Independent understands that Ms Gillespie’s comments have caused considerable disquiet in Garda Headquarters, particularly the suggestion that members of management are responsible for some of the difficulties she has faced.

A number of sources last night said they want to know whether the comments made were in Ms Gillespie’s personal capacity or whether they are shared by the Policing Authority as a whole.

The Policing Authority did not respond to queries from the Irish Independent.

However, in February its chairperson Josephine Feehily declined to express full confidence in Ms O’Sullivan and Garda management pending the outcome of the Disclosures Tribunal.

“I would say we have a degree of confidence, but we are concerned,” Ms Feehily said.

Ms O’Sullivan is due to return to work today, having enjoyed a five-week holiday.

She will undoubtedly face questions in the coming weeks over her failed application for a specialist post in Europol, the EU policing body.

Ms O’Sullivan has also been at the centre of several other controversies, including the Templemore ‘slush fund’ scandal, the Garda whistleblower controversy and the revelations that almost one million breath tests were falsified.