The formation of Sudan's unity government has been delayed yet again, prompting fears that the northern government in Sudan is not ready to commit to power sharing with the former southern rebels.

The formation of Sudan's government of National Unity as part of a January peace deal, has been delayed again. On Thursday Sudan's government-run news agency (SUNA) reported the government would be formed by the end of the week.  But on Sunday, the incoming government still had not assumed power.

Analysts here say the delays are due to a power struggle for control of Sudan's Ministry of Mining and Energy. The northern National Congress Party and the former southern rebel group, the Sudan People's Liberation Movement, are wrestling for control of the ministry, which handles oil production and revenue in Sudan.

Sudan's peace agreement has spurred investment in the nation's oil reserves. The agreement, though, did not specify which party would assume control of critical ministries.

Professor Abendego Akok, the director of the Juba University Center for Peace and Justice Studies, says the Northern National Congress Party may not be ready to commit to power-sharing by relinquishing control of the ministry.

"The National Congress think it is a part of the game for them to remain in power,” said Mr. Akok.  “That is one of the strategic ministries that they cannot give up, so they can cling to power, then propagate in the near future. The southerners think that the northern government may not be so honest to implement the agreement. There is a lack of confidence. There is a great mistrust between the north and the south."

Mr. Akok says much of the mistrust stems from the fact that the dealings of the Ministry of Energy and Mining have, in the past, been shrouded in secrecy.

"The Ministry of Energy and Mining has a lot to do with oil, those who made the pipelines and where the oil is being sold,” Mr. Akok added.  “No one is aware of who is purchasing the oil. Nothing has been revealed about the oil revenue. We have never heard anything about oil revenue."

The unity government was originally to have been formed on August 9. That date was delayed by the death of Sudanese Vice President and former southern rebel leader John Garang. Mr. Garang died in a helicopter crash on July 30, and was succeeded by his deputy Salva Kiir.

Sudan's peace deal put an end to 21 years of civil war between north and south Sudan.