A senior NCP official Mandoor Al-Mahdi said that the southern Sudan administration run by Sudan People Liberation Movement (SPLM) is using intimidation against potential voters in Khartoum and also those urging southerners to register.

Al-Mahdi alleged that SPLM members were present at voting stations telling southerners in North not to register.

He noted that these violations were reported to the South Sudan Referendum Commission to rectify the situation but no action was taken so far.

The presidential adviser and NCP figure Al-Sheik Beesh told state-run SMC news agency that they will not recognize the outcome of the referendum if the registration process continues in this non-transparent manner.

Another senior NCP official Rabie Abdelati on Sunday emphasized that low registration of southerners living in the north would affect the credibility of any outcome.

"The SPLM is using tools to pressure and threaten and terrorize people not to register and this means ... that the whole referendum will not be free and fair and transparent," Abdelati said.

"If this behaviour continues by the SPLM ... this will not lead to an atmosphere conducive to holding the referendum and ... the results will be affected. This will ultimately lead to non recognition not only by the Sudan government but by the whole international community."

Two SPLM officials who want to remain anonymous confirmed to Reuters that it had told southerners in the north not to register, saying they feared the NCP could manipulate results there.

Voter registration began on Monday for the January 2011 referendum on whether oil-producing southern Sudan should secede from the north. It is widely expected that Southerners will choose independence.

The referendum commission estimated that around 5.5 million southerners may be eligible to vote, including 500,000 in the north and another half a million abroad.

Unity

The NCP believes many southerners in the north may vote for unity whereas a majority in the south will vote to secede but polling stations in Khartoum were empty as many southerners who live in the Sudanese capital made the trip south to enroll or abstained from registering altogether for fear of intimidation by the ruling party in the North.

Khartoum governor Abdel Rahman al-Khidr said that only about 1,000 southerners registered in the capital on November 15, when registration opened. Since then the daily numbers had decreased in Khartoum, where most of those eligible to vote in the north live, he said.

However, the SPLM made similar allegations to the NCP for pressuring southerners in the North to vote for Unity. The SPLM’s Atem Garang blamed Sudan for telling southerners to vote for unity.

"It is intimidation. It is against the law," Garang told a news conference in Khartoum. He also denied that they had asked Southerners in the North to boycott the registration process.

"The southern Sudanese, we never urged them not to register because we want them to be free. When we talk about a free and fair referendum, it means when you are going to registration you must be free. We did not to talk to them to boycott the registration," Garang said.

The referendum which may divide African’s largest country was part of the 2005 deal that had ended Africa’s longest civil war that killed about two million people and displaced another four million.