Northern Ireland Policing Board chair Deirdre Toner has said the recruitment of a new chief constable for the PSNI will be prioritised.
She was speaking after an emergency meeting of the board that earlier heard of the resignation of Simon Byrne as PSNI Chief Constable.
Ms Toner confirmed that Deputy Chief Constable Mark Hamilton will exercise all of the functions of the chief constable in the interim.
She said the board has also agreed to initiate a review of the senior leadership team of the PSNI and request the Department of Justice to commission a review of the Policing Board.
"There is a strong commitment and desire within the board to bring stability to the Police Service of Northern Ireland and the steps agreed above are designed to do this, as well as deal with concerns that have been expressed around the operation of the Policing Board," she said.
Mr Byrne resigned following a series of controversies, including a major data leak and the unlawful disciplining of two junior officers.
The announcement by the NI Policing Board came weeks after the police force accidentally shared the names and work locations of every member of staff in a major data breach.
The surnames, initials, work location and department of each staff member were included in error in response to a freedom of information request.
The breach was hugely sensitive in Northern Ireland, where police officers are still sporadically targeted by dissident groups in bomb and gun attacks.
Ms Toner confirmed during a press conference that Mr Byrne had tendered his resignation with immediate effect and read a statement on his behalf.
The statement said: "The last few days have been very difficult for all concerned.
"Regardless of the rights and wrongs, it is now time for someone new to lead this proud and resolute organisation.
"Can I thank those who have shown me trust, advice and friendship, and, of course, thanks to the brave men and women of the Police Service of Northern Ireland."
Ms Toner thanked Mr Byrne for his work over the last four years as chief constable and said he is "undoubtedly a dedicated police officer with a deep respect for the profession of policing".
Mr Byrne faced additional pressure after court last week found he had unlawfully disciplined two junior officers who arrested a victim of a 1992 sectarian shooting in Belfast, while policing a wreath-laying event to mark the anniversary of the attack.
Mr Justice Scoffield said he was persuaded the officers were disciplined to avoid republicans withdrawing their support for the police force.
The DUP last week called for Mr Byrne's resignation.
Read more:
Embattled PSNI chief finally runs out of road
Confidence in chief constable 'irreparably shattered'
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The Police Federation for Northern Ireland, a representative body for officers, said it was considering holding a vote of no-confidence in Mr Byrne.
In a statement following his resignation the chair of the Police Federation Liam Kelly said: "The Ormeau Rd Judicial Review and the shocking potential course of action following the Policing Board was the final straw for Mr Byrne.
"The ruling was damning, and his initial acceptance followed by a volte face around a potential legal appeal grievously undermined his credibility and authority to lead the PSNI.
"It called into question his judgement, decision-making abilities and made his position untenable.
"On a personal level, Mr Byrne has always been approachable and courteous. He has provided over 40 years of policing service to the communities across the United Kingdom.
"I do not doubt his commitment and attempts to build a modern, strong, community-focused service during his tenure in Northern Ireland."
A planned public meeting of the NI Policing Board scheduled for Thursday, which Mr Byrne was due to attend, has been cancelled.
Ms Toner said the last few weeks must have been "incredibly difficult" for Mr Byrne.
"He was very aware of and greatly appreciated the often difficult job that officers and staff across the organisation do on behalf of the community," Ms Toner said.
"This may not always have been apparent to onlookers but it was very much his modus operandi, as was his desire to improve policing for the community through modernisation and investment in local policing arrangements.
"His tenure was subjected to intense scrutiny and I am sure that the last few weeks in particular have been incredibly difficult for him personally and professionally."
UK government may have to approve new chief
Powers would have to be taken by the British government to approve any new chief constable in Northern Ireland in the continued absence of an executive at Stormont, Parliament has been told.
Parliamentary under-secretary of state at the Northern Ireland office Jonathan Caine said that in the "unfortunate circumstance" the devolved institutions were still not up and running when any appointment was made, then it would fall to the UK administration to ratify the chosen candidate.
There have been no functioning devolved institutions since last year when the DUP withdrew from the powersharing arrangements in protest over the post-Brexit trading arrangements for Northern Ireland.
Responding to questions in the House of Lords on the PSNI data breach, Mr Caine said the appointment of a new top officer was a matter for the region's policing board.
He said: "I am sure that they will wish to seek a resolution to this issue very quickly. What is important is that the PSNI has strong leadership restored as quickly as possible."
"It is within their power to appoint an interim chief constable while the formal recruitment process is ongoing," he added.
However, Mr Caine said that "in the unfortunate circumstance that the appointment be made before the executive is reestablished we would have to take powers for the (UK) Government to ratify any appointment that would normally be ratified by the justice minister, which is something that happened back in 2019 when the outgoing chief constable was appointed and there was no executive and assembly functioning."
"We need an executive back in Northern Ireland as quickly as possible," he said.
"We are doing everything we can to bring about that. That would obviously include the appointment of a justice minister within the department who could give political direction," he added.
With additional reporting by Reuters and PA
