Almost 99 per cent of south Sudanese have voted to split away from the north in a referendum, according to the first official but incomplete figures published by the vote's organising commission.

The results were the latest indication of a landslide vote for southern independence in last week's referendum, promised in a 2005 peace deal that ended decades of north-south civil war. The final official figures are expected in February.

The website for the Southern Sudan Referendum Commission (http://southernsudan2011.com/) showed a 98.6 per cent vote for secession, with more than 80 percent of the votes from the south counted, and 100 percent counted in other areas.

Commission staff confirmed the authenticity of the website and the figures. "These are incomplete and provisional pending the declaration of preliminary and final results. They may be subject to change," a statement on its homepage warned.