The deadlock threatens to prolong a crisis in a region dogged by nearly two decades of conflict.
The M23 rebels, who want to overthrow the government in Kinshasa, captured Goma last week after Congolese soldiers withdrew and UN peacekeepers were forced to give up defending the city.
The Ugandan military, which has co-ordinated talks with M23, said rebel leader Colonel Sultani Makenga had agreed to withdraw from Goma with no conditions.
But M23's political chief, Jean-Marie Runiga, said yesterday his forces would withdraw only if Mr Kabila held national talks, released prisoners and dissolved an electoral commission – a body accused by Western powers of delivering Mr Kabila a second term in 2011 in a flawed election.
The conflicting statements indicated a quick solution to the insurgency in eastern Congo, which has displaced thousands of civilians, was not close.
Lambert Mende, Congo's Government spokesman, dismissed M23's demands.
He said: "It's a farce. If each day they're going to come back with new demands, it becomes ridiculous."