By Abdel Moneim Abu Edris Ali (AFP) – 7 hours ago

KHARTOUM — Sudan's parliament adopted a key law on Tuesday, setting up a planned referendum on southern independence after northern and southern leaders overcame a dispute that had threatened a 2005 peace deal.

The new version of the law includes a contested provision demanded by southern politicians that requires diaspora southerners to cast their ballots in the south at the referendum promised for 2011.

Southern parliamentarians had insisted on that provision, fearful that if large numbers of southerners voted in the north there could be fraud and pressure by the Khartoum government.

The new article states that south Sudanese living outside the south and born before January 1, 1956, the date of Sudan's independence, must vote in the south.

But south Sudanese living outside the south and born after January 1, 1956 would be able to vote in their place of residence, whether in the north or abroad.

There are about 520,000 south Sudanese -- mostly Christian -- living in the Muslim north, according to a northern government census. The southern government says the figure is much higher.

The ruling northern National Congress Party (NCP) had deleted the provision in a previous version of the law adopted last week, allowing for absentee votes.

It claimed the article "violated the interim constitution which gives every Sudanese freedom of movement from one region to another."

But the move had prompted a walkout from parliament by MPs from the Sudan Peoples' Liberation Movement (SPLM), the ruling party in the south, and other southern parties.

"Tuesday's amendment has been introduced only to give our southern Sudanese brothers more impetus to vote for the unity of Sudan during the referendum," said Ibrahim Ghandour, a senior official with the NCP.

"It's a new day for the establishment of trust. The people of the south deserve the right to a referendum and more besides," said SPLM deputy secretary general Yasser Arman.

The United States had said it was "deeply concerned" that the earlier text had been stripped of the wording previously agreed with southern politicians.

The new legislation had taken several months of negotiations to formulate.

Under its terms, south Sudan's independence would be recognised if it is approved by 51 percent of voters at a referendum with a turnout of at least 60 percent.

Separately, parliament was due to meet later on Tuesday to vote on a law governing a referendum in the disputed Abyei region, which lies on the north-south border.

The NCP and SPLM, former enemies that now form a government of national unity, had previously pledged to make the unity of Sudan "attractive" to the population.

But calls for independence have increased among southern politicians, who accuse Khartoum of supporting tribal violence in the south.

Sudan's mainly Muslim north and its largely Christian and animist south ended a two-decade civil war with the signing of the Comprehensive Peace Agreement in 2005, after nearly two million people were killed.

The promised independence vote is a key plank of the deal, which also provides for a general election to be held in 2010.

Many in south Sudan are hoping the referendum will grant them independence and want to claim as large an area of the oil-rich Abyei region as possible for the south.

Abyei's population consists mainly of Ngok Dinka tribes, seen as loyal to the south, and Messiriya Arab nomads considered supporters of Khartoum.