Sudan's national unity government has taken office and analysts say the former rebel group lost out on key ministries.
The new administration is made up of 30 ministers drawn mostly from the ruling National Congress Party and the former southern rebel group Sudan People's Liberation Movement.
The new government also includes more than 30 ministers of state and about a dozen special advisors.
Ratios for representation of the ruling party and former rebel group in Sudan's interim government were specified under the terms of a north-south peace agreement signed at the beginning of the year to end more than two decades of civil war.
The National Congress Party now heads the defense, justice, finance, energy and mining, and the interior ministries, while the former rebel group heads foreign affairs, education, and health, among others.
Richard Cornwell is an analyst at the South Africa-based Institute for Security Studies. He says the former government has retained its power by heading the most senior and influential ministries, especially energy and mining.
"Obviously the thing that strikes one is that the old government has not been all that generous, and it may be somewhat shortsighted in the way that it's handled in particular the energy portfolio," he said. "As it is now, the dominance of Khartoum remains visible."
Who controls the energy ministry is a point of contention, as much of the fighting during the civil war was a struggle over the oil-rich fields in the south. Crude oil production in Sudan averaged 343,000 barrels per day in 2004.
An analyst with the International Crisis Group, David Mozersky, says it would have been a positive step for the former rebel group to have headed up the energy and mining ministry.
"Energy issues, petroleum issues, oil in particular, and the successful understanding and cooperation on oil-related issues and in the oil sector are critical for the successful implementation of the peace agreement," he said. "There are definitely problems and misunderstandings between the parties that still need to be overcome. SPLM taking the energy ministry may have helped facilitate some of those problems."
Mr. Cornwell notes that the former rebel group did receive one senior ministry, foreign affairs. But, he says, that appointment was largely symbolic.
"It has given the foreign ministry to SPLM, but this is essentially a P.R. [public relations] function, isn't it? So it can be expected that that would happen in order to ward off criticism of the new government from outside. One would be foolish to imagine that foreign policy is actually made by the foreign ministry," he said.
Mr. Cornwell says he thinks the SPLM foreign minister, Lam Akol, will largely be "interlocutor between Khartoum and the outside on issues such as Darfur."
The interim government is expected to remain in power for about four years, after which legislative elections are to be held.
After six years, the south is to hold a referendum on self-determination.