At the end of a 10-day visit to Congo, UN special rapporteur, Iulia Motoc, said a crackdown on those accused of human rights violations would boost the government's authority.
"The government of Demorcratic Republic of Congo should put an end to impunity to restore the authority of the state across the entire country," Motoc said.
"The human rights situation in Congo is disastrous, especially the regions where armed groups exterminate civilians, rape and loot because of an absence of authority," she said.
She said basic rights were in constant peril in the provinces of North and South Kivu, where group clashes were on the increase.
Acknowledging differences among Congolese leaders about justice and reconciliation, Motoc said a "durable peace is impossible unless the perpetrators of human rights violations are brought to justice."
"The government of should put an end to impunity to restore the authority of the state across the entire country"
Iulia Motoc UN Envoy
Congo's civil war has been marked by extreme brutalities, with some drugged tribal fighters even resorting to cannibalism.
But restoring order in a country riven by ethnic clashes is proving difficult.
Having taken over peacekeeping in the flashpoint town of Bunia from a European force earlier this week, UN peacekeepers faced criticism from local residents for not doing enough to prevent looters from ransacking shops.
The criticism came even as even UN forces fanned out to the town of Bogoro, about 25 kms away.
In renewed violence on Friday, a mob looted several shops and locals said Uruguayan and Bangladeshi troops did little to intervene.
"We ran to the airport for safety but were refused entry. We pointed out the attackers to the UN troops but they did nothing," complained Kashoho Buheke, a victim of the looting.
But a UN spokesman defended their inaction.
"The UN are not the police, they are military. The looters were not armed and imminently dangerous, so we could not open fire," he said.
On arrival at Bogoro, UN troops spotted armed militiamen who then scattered into the bush to hide their arms before joining the welcoming crowd.