The often enemy countries were in the past week reported to be looking at the possibility of jointly deploying forces in the South’s oil-producing regions to rebuff any advances from rebel groups nominally loyal to former vice president Riek Machar.
Sudanese army spokesperson Colonel Khaled Sawarmi told Reuters, however, that past differences between the neighbours was scuppering any such co-operation.
“There is no common ground between the two armies,” he told the news wire.
Deadly fighting has wracked South Sudan since mid-December when President Salva Kiir accused Machar of plotting a coup against him – something the latter has denied.
Fighting spread from the capital Juba to outlying states, with rebels said to still be in control of some oil patches in Unity state, a major oil-producing region.
Residents of the state’s capital Bentiu were said to be on the move this week as government troops advanced on the town. The BBC reported on Thursday that rebels in Bentiu are building up their defences ahead of an anticipated assault.
Peace talks got under way in the Ethiopian capital Addis Ababa recently, but have so far largely proved fruitless, as the parties differ on the issue of political prisoners held by the Juba administration.
South Sudan split from Sudan in July 2011, taking with it three-quarters of the original country’s oil reserves. Khartoum relies heavily on revenues from oil production in South Sudan, which must use its neighbour’s midstream and port infrastructure for exports.