The Sudan Liberation Army (SLA) faction led by Ahmed Abdel Shafie also said it rejected the peace process led by U.N. and AU envoys Jan Eliasson and Salim Ahmed Salim.

The SLA said the rebel factions needed to hold unity meetings in Darfur before any further talks outside the country.

Shafie said they had been talking night and day to the U.N. and African Union, giving them lists of commanders and coordinates to return them to in Sudan's west. But they had been stuck in Juba since the unity talks ended on December 14.

"They say they are looking for permission from the authorities and we told them clearly that for Darfur we don't need permission from Khartoum because we are going to Darfur and to our areas," he said on Tuesday.

The U.N.-AU mediation team denied they were to blame, saying the rebels had given some wrong coordinates and officials were in Juba to deal with the correct coordinates.

"We are working on those coordinates to get the clearance, flight details and all the nitty gritty," said spokesman George Ola-Davies. "It's not an easy task."

The talks ended with many individual commanders coming under Shafie's leadership. But other factions also consolidated, leaving five main groups.

Mediators want all groups to attend talks to agree a ceasefire that will hold.

International experts estimate some 200,000 have died and 2.5 million been driven from their homes in almost five years of rebellion. Khartoum says Western media exaggerated the conflict and puts the death toll at 9,000.

Shafie said they were optimistic about unity of the five groups and said were directly and indirectly in touch with three other groups but had no contact with the powerful Justice and Equality Movement.

But he said any talks had to be in Darfur and dismissed the U.N.-AU mediation as a "waste of time".

"I don't that they will be successful," he said. "This kind of approach will not achieve peace in Darfur -- they need to change the team, the mechanism, the approach."

Mediators want to hold internal rebel talks in an African country within about six weeks but only two of the five groups have so far said they will attend. Peace talks in Libya last year ended quickly as most rebel groups stayed away.

Shafie, a Muslim, said his faction would also insist on the separation of religion and state in Sudan, which has been under Islamic sharia law since 1983.

He said central government had misused Islam for political means.

"We don't see any link between politics and Islam in the country," he told Reuters in an interview. "We call for a clear separation between political practice and religious practice."

He said all the movements agreed on this point apart from the Justice and Equality Movement led by Khalil Ibrahim.