KHARTOUM, Oct. 5 (Xinhua) -- Sudanese parliament speaker threatened on Monday to table a bill on the referendum on the self determination of southern Sudan in case two major political partners failed to agree on the legislation.

Ahmed Ibrahim al-Tahir was referring to the differences between the ruling National Congress Party (NCP) and the Sudan People's Liberation Movement (SPLM) which runs the southern Sudan government.

Addressing the ninth session of the Sudanese parliament, al-Tahir said "the parliament has run out of patience as it is waiting for the political forces to agree on the points of difference."

The parliament, "in response to its duty in endorsing this bill during this last session, will be forced to table the bill if differences around it remain," he said.

"Guaranteeing the right of the southern Sudan sons to cast their votes in the referendum remains a duty on us and it should be fulfilled, no matter what the results were."

"The transitional constitution places on the national legislative council the responsibility of issuing this law to prepare the country for the referendum in 2011," the speaker said.

Chairperson of the SPLM parliamentary bloc Yassir Arman criticized al-Tahir's remarks, saying that the parliament does not have the right to endorse the referendum before the SPLM reaches an agreement with the NCP.

"If such a thing happens, it would be a serious violation of the Comprehensive Peace Agreement (CPA) and the Transitional Constitution," he told reporters.

Arman said the SPLM will make necessary responses to any move to pass a bill for the referendum that the SPLM disapproves, saying "the referendum law should be agreed on by the SPLM and the NCP."

The NCP and the SPLM differ on all essential points of the referendum law, notably on who has the right to vote. The NCP argues that all southern Sudanese people, wherever they are, have the right to vote and that this right should not be confined to the SPLM members.

Another difference is over the headquarters of the referendum commission. The NCP insists that the CPA stipulates that the commission is to be based in Khartoum, while the SPLM demands that a sub-office be established in southern Sudan to be responsible for the state offices.

The most serious rift, however, is over how the referendum is to be decided.

The NCP demands separation be decided by more than two thirds of the registered voters and that unity by a simple majority, while the SPLM insists both separation and unity should be decided by a simple majority.