Restorative Justice groups from republican areas of Northern Ireland have declined to attend a conference organised by the police.
Schemes can see offenders meet victims
Loyalist representatives will be among 200 delegates at the international meeting in Belfast on Monday.
Restorative justice can involve perpetrators meeting their victims.
Provisional figures from a NI pilot scheme suggest a quarter of cases which could be prosecuted, could be dealt with through restorative justice.
Chief Inspector Nigel Grimshaw, of the Police Service of Northern Ireland, said restorative justice was about "respect".
"It is about bringing people together who have been affected by crime and conflict through a process which encourages taking respect and showing respect for other people," he said.
Inspector Grimshaw said this was no "soft option" for offenders.
"Having to sit down, face to face, potentially, with the victim of your crime and listen to their story and the consequences of your actions is a very emotional and dynamic thing."
He added that the police had been keen to engage those working in republican areas in the conference.
"Restorative justice is an inclusive process. Those working in restorative justice schemes in republican areas clearly have a stake," he said.
However, Inspector Grimshaw said an array of speakers had been brought together for the two-day event which, he hoped, would provoke "real thought and debate".
The provisional figures are from the Public Prosecution Service pilot scheme which is operating in south Belfast, Fermanagh, Tyrone and all youth courts in Belfast.
The chief inspector said that in the Belfast court area, approximately one in four young people were currently undergoing a restorative process in terms of offending behaviour.
On Monday, delegates will explore advances in restorative justice within Northern Ireland and, on Tuesday, the focus will shift to examine community approaches to restorative justice.