The new Garda commissioner has described findings from an investigation into corruption in the force as a "clarion call" for action.

Drew Harris said he felt the stark remarks made in the final pages of the Disclosures Tribunal report were almost written directly to him.

In his first appearance before the Justice Oireachtas Committee since taking up his role as commissioner two months ago, Mr Harris said whisteblowers will be treated with the "utmost seriousness".

The Disclosures Tribunal found former Garda commissioner Martin Callinan was part of a "campaign of calumny" against Sergeant Maurice McCabe.

The report said he was actively aided by his former press officer, Superintendent David Taylor.

Mr Harris said he spoke to Sgt McCabe by phone on the day the report was published and was due to meet him yesterday.

The former deputy chief constable of the PSNI addressed some of the concerns raised in Mr Justice Peter Charleton's report.

"I have read it and in particular I read the last few pages, which I feel were almost written directly towards me and they are a clarion call for action," he said.

"Cultural change comes from behavioural change and my behaviour and that of the leadership team have a dramatic impact on the organisation.

"We wish to follow through in completely overhauling our discipline code, which creates an atmosphere of people fearing that discipline, as opposed to proper management intervention and a learning organisation, to an organisation which is punitive towards its staff.

"There is structural systemic changes we need to make about how the organisation is run but I also emphasise if any individual wishes to come forward and wishes to whistle blow or to make a disclosure then that will be treated with utmost seriousness and I am open to individuals should they wish to speak to me."

He said everyone in the force is undergoing code of ethics training to be completed by the end of the year.

Mr Harris told the Justice Committee that while An Garda Siochána is a disciplined force, it is "not helped" by its current procedures, which he said was not fit for purpose.

"Instead of discipline where we are intervening around poor performance, (we must ensure) that we are intervening appropriately in either support, supervision, training or management intervention," he said.

"But in cases of serious misconduct where your trust in an individual is entirely broken then they have no place in the organisation."

In addressing concerns around the force's preparations for Brexit, Mr Harris said the border region is appropriately staffed, adding 180 staff members are due to graduate from Templemore College next month.

He said people living in border communities are concerned about local policing and there were also fears of travelling criminals crossing the borer.

"There is also the reality of the nightlife in Derry where there are a lot of young people who travel across the border and engage in nightlife," he said.

"There is also the concern that they (paramilitaries) might use this (hard border) as an emotional driver for their particular campaigns and we want to avoid it being used as a rallying call.

"We are still not sure what the nature of Brexit is going to be so there is an unknown element of this and we have prepared as best we can for that."

Donnchadh Ó Laoghaire, Sinn Féin TD, said following Mr Harris' appointment as Garda commissioner a number of Northern Ireland victim groups raised concerns.

"They viewed you as someone who blocked their access to truth and justice when you were the key person within the PSNI responsible for legacy issues," Mr O Laoghaire said.

Mr Harris told the committee he is willing to meet victims and he has a number of pending invitations.

"I will work with the various coroners' inquests and other avenues which are ongoing at the moment in Northern Ireland around inquiring into matters during the Troubles," he said.

Mr Harris was further pressed by Mr Ó Laoghaire on his previous roles within the PSNI, the Royal Ulster Constabulary and the MI5 British security service after a number of people questioned his suitability to be head of the gardaí.

Mr Harris said he was subjected to "a very high level" vetting process for two decades that was "under constant renewal".

"There is no issue about the level to which I have been vetted," he said.

Jack Chambers, Fianna Fáil TD, asked Mr Harris if he felt that some of the questions posed by Mr Ó Laoghaire were of "sectarian prejudice".

"Have you felt that certain elements are trying to undermine your position?" he said.

Mr Harris said he has addressed questions that have been subject to much commentary.

"Some of that commentary has been ill-founded," Mr Harris said.

"I swore an oath and that oath is important to me. I am here to serve and protect the people of Ireland."