JUBA, Sudan (AFP) – Foreign observer missions on Monday endorsed the credibility of south Sudan's landmark independence vote to the delight of the region's ruling party, although it held off on declaring victory.

Poll observers from both the European Union and the six-nation east African bloc that helped broker the 2005 peace deal which provided for the referendum said it had been "credible."

The Arab League mission and the Carter Centre foundation of former US president Jimmy Carter said the week-long vote on partitioning what is both Africa's and the Arab world's largest nation had broadly met international standards.

The Carter Centre, which has the largest foreign observer mission, added that a vote for secession was "virtually certain" based on early results posted by polling stations, which were wrapping up their counts on Monday.

"We are happy that the international and local observers have made the observation that the referendum was free, credible and transparent," the secretary general of the ruling, former rebel Sudan People's Liberation Movement, Pagan Amum, told AFP.

Amum, who is the south's pointman for the implementation of the 2005 peace deal with the north, declined to be drawn on Carter Centre's prediction of a majority for secession.

"We are waiting for the results to be announced, we don't want to go to speculation," he said.

In its assessment, the Carter Centre said: "Overall, the referendum process to this point has been successful and broadly consistent with international standards.

"Based on early reports of vote counting results, it appears virtually certain that the results will be in favour of secession."

Partial results from the southern regional capital Juba showed a landslide for independence, but the final verdict is not expected before next month after the votes have been collated from across the vast, war-ravaged region.

"The results of the polls are still being collected and there can be no official result of the referendum at this time," commission deputy chairman Chan Reec told AFP.

"Preliminary results for the south are expected to be released at the end of January and the final results on February 14," he added.

Polling stations across the south were due to complete their counts on Monday, triggering the huge logistical effort of bringing in the ballots to centres in a region that has just 40 kilometres (25 miles) of paved road.

The EU observer mission said the vote had been "peaceful and credible," but said it would hold off on judging whether it had met international standards until after the count was complete.

The East African observer team said it was "satisfied that the counting was done in a free and transparent manner."

The Arab League's team said there had been some glitches, including underage voting and propaganda inside polling stations.

"These drawbacks do not affect the veracity of the process, which was characterised by a high degree of transparency and integrity in line with international standards, eliciting respect for the outcomes produced by the ballot box," it said.

The foreign observers' endorsement of the conduct of the referendum contrasted sharply with their assessment of general elections across Sudan last April. Observers then reported widespread intimidation of voters.

The south's internal affairs minister Gier Chuang held UN-facilitated talks with Sudanese Interior Minister Ibrahim Mohammed Ibrahim in the northern town of Kadugli aimed at quelling deadly violence in and around the disputed district of Abyei on the northern border, a UN spokesman said.

They were joined by leaders of the district's Misseriya Arab nomads and pro-southern Ngok Dinka farmers who have clashed repeatedly since January 7 resulting in up to 38 deaths.

UN humanitarian coordinator Georg Charpentier said on Saturday that the aim was to "ensure that the flow of return through the south... is done smoothly, and at the same time that the Misseriya -- the nomadic groups -- can indeed engage as usual, beginning January, in their migratory movement to the south."

The south has suspended returnee convoys through the area after a bus ambush killed 10 people.

Abyei had been due to hold a plebiscite on its own future alongside the southern referendum. It has been indefinitely postponed.