Our correspondent reported that differences emerged between them during the current round of talks. An attempt would be made in the meeting next month to resolve these differences.
SPLA spokesman Yasser Arman said on Friday the talks had reached a stalemate after the Sudanese government refused to negotiate on the basis of a document drawn up by an east African regional body.
The government delegation maintains the document, by the Inter-Governmental Authority on Development (IGAD), should not be referred to in the talks.
But the SPLA insists the text must be the basis for attempts to reach a settlement ending Sudan's 20-year civil war.
"The draft document is the result of nine months of intensive negotiations with the IGAD mediators but the government delegation now wants it to be set aside, a condition the SPLA will not accept," an SPLA source said.
As the talks began last Sunday, Sudanese President Omar el-Bashir warned he would not sign an "unfair" peace agreement, and said he had "doubts" about the real intentions of SPLA leader John Garang.
Bashir said Khartoum would resort to other unspecified "options" should the deadlock persist.
"We are not going to sign any peace agreement that does not implement justice," he said.
"The draft document is the result of nine months of intensive negotiations but the government delegation now wants it to be set aside"
-- SPLA source
Bashir has repeatedly cast doubt on the neutrality of the mediators from IGAD - whose members are Djibouti, Eritrea, Ethiopia, Kenya, Sudan, Uganda and Somalia - since the talks began.
Issues still unresolved include power-sharing, the distribution of wealth, security arrangements and the future of three areas in the centre of the country where the rebels are active.
The SPLA claims it has the mandate to negotiate on behalf of the people of Abyei, the Nuba Mountains and Southern Blue Nile.
But Khartoum claims it controls 90 percent of the three territories.
Failure to resolve any of these issues was responsible for the breakdown of the last round of talks in the Kenyan town of Nakuru in July.
Khartoum has rejected a proposal that both the government and the SPLA maintain separate armies during a six-year transition period, saying this would amount to secession of the rebel south.
The SPLA has been fighting Khartoum forces since 1983. At least 1.5 million lives have been lost in the conflict.