Carter said there was no doubt about the legitimacy "as far as the number of voters is concerned". (AFP)
Organisers of a landmark south Sudan independence vote confirmed Thursday the turnout threshold needed for it to be valid has been reached as ex-US president Jimmy Carter said the region looked set for nationhood.
"It has reached 60 per cent and even more," referendum commission spokeswoman Souad Ibrahim told AFP after Carter, who has been heading an observer mission for the vote, endorsed claims by the south's ruling former rebels that the threshold had been reached.
"That criterion has already been reached so there is no doubt about the legitimacy of the election as far as the number of voters is concerned," Carter told reporters.
"I think it will meet international standards both on the conduct of the vote and the freedom of voters," he said, adding he expected the same to be true of the count.
"The likelihood is that the referendum result will be for independence although we won't know until probably the first week of February," the former US president added.
Cars draped with the black, red and green southern flag and banners calling for separation honked their horns as they criss-crossed the potholed dirt tracks of the regional capital Juba, although it was not clear if campaigners were immediately aware of the confirmation the vote would be valid.
Carter said the challenge now was to address the outstanding issues between the two sides swiftly ahead of the July date for international recognition for the south set by a 2005 peace agreement with the north.
"(Southern president) Salva Kiir has told me he is now ready to go into negotiations... probably under the chairmanship of (former south African president Thabo) Mbeki," Carter said.
"I believe that will happen quite quickly after the results are known."
Carter played down violence in and around the flashpoint district of Abyei on the north-south border over the first few days of the week-long polling period, including a deadly ambush against southerners returning from the north for the vote on Monday evening.
"A few going through Abyei have been actually been physically attacked. That is actually quite a tiny proportion," he said, noting 160,000 returnees had already come home and that that number was likely to rise as independence loomed.
He said he did not believe the northern or southern leaderships were behind the clashes in Abyei itself which killed a total of 33 people from Friday to Sunday.
"The reports I have so far are that the national forces of both north and south have been very careful not to get involved in the violent confrontation in Abyei," he said.
"I have had no reports of any further violence in the past 24 hours.
"It would be very damaging for (Sudanese President Omar) Al-Bashir's government if he were accused of precipitating violence."
The deputy secretary of the south's ruling former rebel Sudan People's Liberation Movement, Anne Itto, on Wednesday accused the government in Khartoum of backing Arab militias in Abyei.
"I condemn the attacks on the Abyei villages," she said, charging northern troops had taken part alongside militiamen of the Popular Defence Forces and nomadic Misseriya Arab tribesmen, who have been fighting settled pro-southern Dinka farmers for control of the territory.
"The idea is to discourage Abyei from wanting self-determination, and I think it is not right at all to subdue people by force," she said.
The district had been due to hold a plebiscite of its own on whether to go with the south or the north, but that has been indefinitely postponed because of disagreement between northern and southern leaders over who should be eligible to take part.
The Misseriya, who migrate to Abyei each dry season to find water and pasture for their livestock, insist they should have the same right to vote as the Dinka, who live in the district all year.
Dinka and Misseriya leaders were due to hold a second day of talks in the South Kordofan state town of Kadugli in the north to discuss their differences over Abyei.