Former Libyan leader Moammar Gadhafi died last year after falling into rebel hands. NATO forces in early 2011 intervened in a civil war that eventually paved the way to the first new government in a generation.
Tarek Mitri, the head of the U.N. Support Mission in Libya, said national reconciliation involves more than temporary fixes.
"Reconciliation is necessary for establishing security and launching human development in all its dimensions," he said in a statement. "It is a forward looking and long-term process."
The Tripoli Post reports Thursday that military prosecutors have charged Mustafa Abdul-Jalil, the former chairman of the interim government, in connection with the death of Abdel Fattah Younes, Gadhafi's former interior minister who later defected. Trials are under way for other former regime officials accused of war crimes during last year's war, including Gadhafi's son, Saif al-Islam.
Mitri said post-war truth and justice mechanisms must strike a balance between amnesty and revenge.
"This process, if managed well without haste or partisanship, can set the broad lines of a new social contract that would be the first cornerstone of the new constitution," he said.