Juba - Floods have displaced nearly 60,000 people in the last month in south Sudan with many at risk of malaria and other diseases, the semi-autonomous region's government said on Tuesday.

The crisis is another hurdle for the war-ravaged south ahead of a referendum on independence in January, which some analysts fear will be hindered by a worsening humanitarian situation with almost half the region's 8 million population short of food.

The south's health minister, Luka Monoja, told a news conference that rains were expected to continue until October, meaning the worst may be yet to come.

Northern Bahr El-Ghazal is due to receive some of the 1.5 million people the government plans to bring home from the north before the January vote.

The United Nations says it has already helped feed some 4 million southerners in 2010 and warns voting preparations may heap more stress on the region.

Analysts fear the mounting humanitarian crisis will add to problems of insecurity ahead of the January 9 vote and destabilise a newly independent state should the referendum pass.

The mainly Christian and animist south has fought a bitter civil war against the mainly Muslim north over ethnicity, ideology and resources for all but a few years since 1955.

The plebiscite is the climax of a 2005 peace deal ending Africa's longest running civil war.