But in the end the other 20 other armed groups invited by Kinshasa did not turn up.
Opening the talks, Moses Wetangula, Kenya's foreign minister, told both parties that the international community supported a peaceful solution to the crisis.
"Please don't let Africa down. Don't let your country down," he said. "Let this be the beginning of the end."
The talks, which were expected to continue on Tuesday, are the first time the warring parties have met face-to face.
Olusegun Obasanjo, the former Nigerian president and now the UN special envoy for eastern DR Congo's conflict, urged both sides to resolve the conflict.
"It is an opportunity that must not be missed. A military solution is not an option, but nor is the status quo" he said.
Nkunda declared a unilateral ceasefire in late October when his fighters were on the verge of overrunning Goma, the provincial capital of North Kivu province.
"We would like to talk quickly and go back home as quickly as possible, even though there are many issues to solve," Rene Abandi, CNDP foreign affairs spokesman, said, urging the Kinshasa government also to formally sign the ceasefire.
Clashes have continued between Nkunda's fighters and the local pro-government Mai Mai militia and Rwandan Hutu rebels despite the ceasefire.
The talks took place as the European Union discussed whether to send peacekeepers to the region.
The United Nations wants to bloc to supply a "bridging force" until their own reinforcements arrives, but no country has stepped forward to lead the mission.
The United Nations has deployed about 17,000 troops in DR Congo and plans to send around 3,000 reinforcements, but they are expected to need four months to deploy.
Britain and Germany were believed to be against sending troops to provide the short-term security in the east of the country.