Zainab Hawa Bangura, U.N. special envoy on sexual violence in conflict, said challenges to address the issue in DRC remained severe.
"I am concerned about the scale of sexual violence in conflict in the Democratic Republic of the Congo but I have also been encouraged by the steps taken by the government and the work being done by the U.N. and other international and national actors," she said in a statement.
The International Criminal Court last year issued an arrest warrant for DRC rebel leader Bosco Ntaganda on charges including rape and sexual slavery. He surrendered to the court in March.
Bangura met in DRC with British Foreign Minister William Hague, who said the consequences of sexual violence in the country were unimaginable.
"The Congo cannot let its image be tarnished and taken hostage by criminals committing sexual violence," she added.
The U.N. Security Council authorized an intervention brigade for its peacekeeping mission in DRC that has the authority to take on armed groups in the country. DRC rebels seized eastern territory last year and violence has since resurfaced.