Criminal investigations into Troubles-related murders must not be sacrificed for any truth and reconciliation process, nationalists and unionists insisted last night.
Chief Constable Hugh Orde, had admitted last night that the killers behind 1,800 murders were unlikely to be caught and suggested a truth commission as a form of closure for victims' relatives.
But victims' groups and politicians said at-large killers must not be offered an amnesty by a truth commission.
Mr Orde said the number of serving police officers in Northern Ireland meant there was little chance of securing convictions on more than 1,800 murders.
"I have made it very clear when I have met families of victims that in an evidential sense we are going to be struggling to secure convictions," he said.
"A conviction is an unlikely outcome even if you put a lot of resources for a long period of time into one or two cases."
He said one way forward was a truth forum, where paramilitaries, victims and security forces could come forward and speak publicly about the past.
"There needs to be something that gives everyone an opportunity to say their piece, to get the best explanation they can on what happened to their families, their loved ones so they can then get on with their lives," he said.
However, SDLP Policing Board member Alex Attwood said people's right to justice could not be forfeited if a commission was established.
"Everyone who has lost someone is entitled to both truth and justice but it is going to be difficult to bring to justice to all those who have been guilty of abuses," he said.
"The SDLP has been saying for some time that there should be some truth process so that victims can be more fully recognised and some further efforts made to get to the truth.
"But it cannot be that people's right to justice be arbitrarily abandoned."
Ulster Unionist MP Jeffrey Donaldson said he believed there would be a frosty response to the Chief Constable's suggestion.
"I think that victims are entitled to proper justice. Is the Chief Constable telling the relatives of RUC victims that those cases should now be set aside?" he said.
"In the context of Northern Ireland there is little point in having a truth and reconciliation commission. All these various inquiries are doing is reopening the wounds of 30 years of conflict."
William Frazer of the south Armagh victims group Fair, and whose UDR father's murder remains unsolved, claimed families were outraged at the proposal.
"No-one has the right to tell people to put the past behind them," he said.
"His duty as Chief Constable is to make sure that every murder case is investigated thoroughly."
