First Vice-President Ali Uthman Muhammad Taha and rebel leader of the Sudan People's Liberation Army (SPLA), John Garang, have both been at the talks in Nairobi since 7 October.
The talks are aimed at ending Africa's longest-running civil war.
"It has been agreed that the principals will return after the holy month of Ramadan," Lazarus Sumbeiywo, the Kenyan chief mediator for the talks, said on Saturday.
The stakes for both sides are high.
The southern rebels have warned that if these talks fail, fighting could break out in the south, east and west of Africa's largest country.
Khartoum, under immense international pressure to finish the south Sudan peace pact so it can solve the Darfur crisis in the west, has said it would like to sign the agreement by December.
Sudanese officials and rebels are
under pressure to produce a deal
Washington has proposed the UN Security Council holds a November meeting in Nairobi to encourage both sides to finish the talks.
Lower-level negotiators will continue to meet to discuss the details of putting the peace pact into practice, Sumbeiywo said.
Diplomats say that includes resolving who will pay for SPLA soldiers brought into joint SPLA-Sudanese military units.
Delegates also said both sides agreed in principle to the disbanding of armed groups but are still split on whether to add them as signatories to a final peace pact.
The parties agreed to approach these groups jointly to work out how they will be disbanded and absorbed into the SPLA or Sudanese forces, delegates said.
Garang and Taha had originally been scheduled to meet for only three days, and then leave the talks to delegates.
"It has been agreed
that the principals will return after the holy month of Ramadan"
Kenyan chief mediator
Delegates said the two had met almost daily, but other diplomats have said the two met only at the opening of the talks and once thereafter.
Garang and Taha stayed in town for 10 days, in part to attend the inauguration of the new Somali president, Abd Allah Yusuf, in Nairobi on Thursday, which both attended.
Oil and power politics have complicated the conflict in Sudan.
In May 2004, the government and the rebels signed landmark preliminary accords on how to share power and manage three disputed areas.