Ten international aid groups, including Oxfam, World Vision, the International Rescue Committee, and Save the Children, have released a report urging sustained international engagement with Sudan's two ruling peace partners in order to avoid a return to conflict.
Oxfam spokesperson Alun McDonald said that the 2005 peace agreement between the North and South is facing an extremely critical stretch.
"We have just seen the end of a year where there has been a huge increase in violence," he said. "There have been growing political tensions between the North and the South, and also within the South itself. The peace agreement which was signed five years ago this week is looking extremely fragile."
The peace deal dictated a six-year interim period during which the southern SPLM rebels would be given semi-autonomous control over the South and during which national elections were to be held. At the end of the interim period, now only one year away, the South is to be granted a regional vote for independence.
The national polls have been pushed back twice and are now set for April. Tensions surrounding the independence vote, which is widely expected to result in a determination for secession, have been pushing the boiling point for several months as arrangements for the contentious referendum are set into law.
Meanwhile, the South has seen an explosion of violence, mostly due to bloody inter-tribal clashes. More than 2,500 were killed during the course of 2009 - many more than in the headline-catching western region of Darfur - and 350,000 have been displaced.
The peace deal was mediated by a number of outside countries, including the United States, Britain, Norway, and regional neighbors. The report accuses these governments of paying little attention to the implementation of the agreement once it was signed.
The head of southern Sudan humanitarian operations for the International Rescue Committee, Richard Poole, says the region needs the international community to re-focus and open serious dialogue with the two sides.
"The more engagement of the international community in this process, the more people are helping to support it, are monitoring the terms of the CPA [Sudan Comprehensive Peace Agreement], supporting both the government of the North and South, the greater the possibility of the referendum going ahead, and an outcome whatever it happens to be taking place peacefully. If the referendum does not go ahead, we can expect a return to civil war," he said.
The 2005 peace agreement ended a 20-year civil war that killed two million people, mostly Southerners. The war broke out after only 10 years of peace, following a previous rebellion that ended in 1972.
A group of aid organizations is warning of a slide back to war in southern Sudan as a landmark peace agreement nears its end. The groups are calling for significant international action to try to salvage the tenuous peace.