A former Sudan rebel group is expressing concern that the lack of progress over renewal of a 2005 peace agreement could cause instability. 

The Comprehensive Peace Agreement (CPA) signed between southern and northern Sudan effectively ended the two-decade war between the warring factions.

But an official of the Sudan People's Liberation Movement (SPLM) is accusing its northern partners of deliberately stalling on key issues of the agreement. The northern Sudanese dismiss the accusation as disappointing.

"The whole situation in Sudan is getting into a very dangerous situation. So it is really very sad to hear one party saying this on the others after this meeting," said Fouad Hikmat, an analyst with the International Crisis Group.

He said there is need for the two parties to find common ground.

"We always need the two together to work out their differences to have that good will and whatever they agreed to be implemented in good faith," he said.

Hikmat said time is limited to reach a full implementation of the CPA.

"It is about how the two parties are going to negotiate the implementation of the key provisions left now, given that the time is very short for the general elections," Hikmat said.

He said the former rebels could not form a party that would have a national appeal.

"The mitigating factor is clear that south Sudan, unfortunately the SPLM, [was] not able to convert themselves into a national political party, and therefore, they are pulled inwardly because of the situation in south Sudan." he said.

Hikmat said a sure way to resolve the impasse between the two parties is to reach a compromise.

"How could we bring these two together? I think the only thing is that that could be done soon through a consensus where all the political forces each can agree on a common agenda," Hikmat said.                                

The CPA controversy comes a week after Washington hosted leaders of northern and southern Sudan to discuss remaining disputes over the peace deal.

Some political observers say they fear Sudan could be dragged into another round of civil war if disputes surrounding the peace agreement are not resolved soon.