About 250,000 people displaced as Tutsi fighers stage advance into east.
On Saturday, Nkunda said he is ready to negotiate with DR Congo’s government.
“There are no conditions, we are asking only for negotiations, direct negotiations with our government and we ask him [Obasanjo] to get us a mediator,” he told Al Jazeera.
“But other things we cannot expect from him, because it will be a matter for talking with our government.”
Obasanjo had already met Joseph Kabila, DR Congo’s president, in the capital Kinshasa.
More than 250,000 people have been displaced by fighting between the army and the CNDP, which claims to be acting in the interest of ethnic Tutsis in the region.
At least 100 people have been killed since fighting broke out in September, despite the presence of about 17,000 UN troops – the largest UN peacekeeping force in the world.
Kinshasa says that the CNDP is receiving assistance from neighbouring Rwanda, a claim that Kigali denies.
There are fears the country could slide into a ruinous war similar to the 1998-2002 conflict that drew in more than half a dozen African nations.
In th wake of that conflict, fighters backed by Uganda and Rwanda seized vast swaths of territory rich in coffee, gold and tin in the east.
Angola and Zimbabwe sent tanks and fighter planes to back DR Congo’s government in exchange for access to lucrative diamond and copper mines to the south and west.
Eastern Congo has been unstable since millions of refugees spilled across the border from Rwanda’s 1994 genocide, which saw more than 500,000 ethnic Tutsis and moderate Hutus slaughtered.