Richard Poole, director of International Rescue Committee humanitarian assistance in southern Sudan, displays a report in Nairobi, Kenya, as aid groups warn of the prospect of renewed civil war in the region. (Khalil Senosi/Associated Press)

Sudan's volatile southern region could once again collapse into chaos if the international community does not do more to strengthen the 2005 peace deal that ended more than 20 years of civil war, aid organizations warn.

The first multi-party elections in more than two decades are set for April, and the groups said in a report released Thursday in Nairobi, Kenya, that a referendum on independence for the south in January 2011 also could re-ignite the war that killed two million people.

The 10 aid agencies, including Oxfam International, Save the Children and World Vision, also worry about disputes between the south and north over oil.

The report, entitled Rescuing the Peace in Southern Sudan, said some 2,500 people were killed and 350,000 others were displaced in 2009 due to an upsurge in violence.

It warned that "a return to conflict would have devastating consequences that extend far beyond southern Sudan."

'This will never happen,' minister says

But Sudan's humanitarian affairs minister, Abdul Bagi Gilani, rejected the possibility of a return to conflict.

"I will say this will never happen because all parties — the National Congress Party and SPLM (Sudan People's Liberation Movement) — are keen not to go to war again," Gilani said.

Sudan is holding its first parliamentary and presidential elections in all regions of the country next April. The elections are a key part of the 2005 deal that ended more than two decades of north-south civil war.

The 2005 agreement created a transitional national unity government, but mistrust runs deep.

The elections are expected to pave the way for the 2011 referendum in which the oil-rich south will chose whether to become independent from the north, another critical point of the peace deal. As part of the peace accord, the two sides agreed to work toward unity.

But southerners, increasingly frustrated at the lack of peace benefits, have openly favoured independence. Many northerners fear that secession of the south would deprive their government of much prized oil revenues.

The agencies urged the international community to mediate between the parties before the elections and referendum are held.