"The persistence of the war in the east of our country risks jeopardizing the electoral process, which is already underway, due to a massive displacement of people from combat zones, the insecurity and the inaccessibility of these areas," Tshisekedi told the U.N. Human Rights Council session.
The fighting has displaced hundreds of thousands of people, raising concerns about the state's ability to prepare for the parliamentary and presidential elections later this year.
Tshisekedi urged the international community to help Congo restore peace and state authority in this part of the country.
He again accused Rwandan authorities of supporting the M23. Rwanda denies backing the rebels.
Three Congolese and foreign electoral experts told Reuters the electoral commission could postpone the polls. It has already delayed the deadline for voter registration twice in more than a dozen western provinces due to technical problems.
Congo's electoral commission started registering voters on Feb. 17 in North Kivu province, parts of which are occupied by the M23 rebel group, a Tutsi-led militia that has been waging an offensive against Congolese troops for almost a year.
Registration has so far been impossible in the territory under M23 control in North Kivu, one of Congo's most populous provinces.
The Congolese government has asked the U.N. High Commissioner for Refugees (UNHCR) to hold discussions between Congo, Rwanda and the U.N. agency about repatriating refugees, Tshisekedi added
