Juba - The president of South Sudan warned Thursday of renewed conflict with former foes in north Sudan if bitter oil negotiations do not include a deal on other key issues, including the contested Abyei region.

"It would not be fair to my people to support an agreement that invites more conflict by failing to resolve underlying issues," Salva Kiir told reporters.

"An agreement that we would consider signing should not only focus on the oil crisis, but be comprehensive to cover all the outstanding issues," he added.

South Sudan in January took the extreme step of shutting down oil production the fledgling nation's top revenue source as it accused rival north Sudan over an oil dispute and African Union-mediated talks remain stalled.

Kiir said he had rejected an offer made last week because it failed to address the future of the contested Abyei region, an area the size of Lebanon which is claimed by both sides but occupied by Khartoum.

"The (proposed) agreement would guarantee future and possibly immediate conflict over land, people and oil," Kiir said.

UN chief Ban Ki-moon said Sunday that tensions and a furious row over oil between the former enemies has become a major threat to regional peace and security.