UN member states have voted Rwanda onto the Security Council, where they will serve for two years.
The country will replace South Africa and occupy the African seat, which was uncontested, on January 1.
On Monday, a leaked UN report accused the Rwandan defence minister of leading a rebel army in the neighbouring Democratic Republic of Congo.
The DRC raised objections to the candidacy of Rwanda, but Kigali has rejected all allegations.
Human Rights Watch also criticised Rwanda’s selection, saying the country can use its seat to block sanctions against itself.
Philippe Bolopion, UN Directorfor HRW told the BBC,
"If they were, after being elected to the UN Security Council, to immediately stop all their support to M23 that would be great news. But nothing in their recent behaviour would suggest that it would happen,"
The leaked UN report says leaders of the M23 rebel group received “direct military orders" from the chief of defence staff Gen Charles Kayonga, who acts on orders from the defence minister.
Uganda is also accused of supporting the rebels.
"Both Rwanda and Uganda have been supporting M23," said the report.
"While Rwandan officials co-ordinated the creation of the rebel movement as well as its major military operations, Uganda's more subtle support to M23 allowed the rebel group's political branch to operate from within Kampala and boost its external relations," it said.
