On Sunday, Tomaz Salomao, head of the Southern African Development Community (Sadc), said members were willing to send peacekeepers to support the DR Congo army.
He said a military advisory team would be deployed immediately and the United Nations would be asked to expand the mandate of its peacekeeping mission, known as Monuc.
"There are fears that the disease will spread ... because these people are not settled"
Mohammed Adow, Al Jazeera's correspondent in DR Congo
Sadc also renewed calls for a ceasefire and the creation of humanitarian corridor.
However, Nkunda insisted his forces were upholding a fragile ceasefire and called on the government to enter into negotiations.
"We declared the ceasefire, and we're still sticking to it," he said.
Al Jazeera's Mohammed Adow, reporting from the Kibati refugee camp, 10km north from the regional capital Goma, said Medicins Sans Frontieres (MSF) had confirmed 48 cases of cholera at that camp alone.
There were about 80 known cases across camps in the region, but the movement of people displaced by the fighting has raised concerns that the localised outbreaks could develop into a full-blown epidemic.
"There are fears that the disease will spread ... because these people are not settled. These are people who are coming out of their homes whenever there's fighting near, they are coming to such camps but they are not here to stay."
Doctors at a hospital in Goma have confirmed two cases among the city's residents, adding to fears the disease is quickly spreading outside the camps.
Dr Claire-Lise Chaigot of the World Health Organisation warned that "all the ingredients are there" for a cholera epidemic.
"We have a serious risk of having a big cholera epidemic in this part of the world ... We have a population that is on the move, an unstable security situation and a population that does not have access to safe water and proper sanitation," she told Al Jazeera from Geneva.
Chaigot said that fresh fighting would further hinder efforts to get aid and medical supplies to people already hard to reach.
The United Nations has a 17,000-strong peacekeeping froce in DR Congo, but is asking for an extra 3,000 troops as the current force is thinly stretched across the country the size of western Europe.
Bernard Kouchner, the French foreign minister whose country currently holds the rotating presidency of the European Union, said "the situation is in decline".
"The humanitarian situation is more than disastrous... will the UN forces be able to deal with it? I don't know," he said.
More than 250,000 people have fled their homes to escape the fighting between government forces and Nkunda's National Congress for the Defence of the People in recent weeks.
Hundreds of people are believed to have been killed in clashes.