John Garang looks likely to take on a major political role as the two sides move closer to a final peace deal to end 20 years of civil war.
Sudan's Energy Minister Awad Ahmad al-Gaz also told a Paris news conference on Tuesday that the government had proposed presidential control over the disputed oil-rich Abyai district.
Al-Gaz said this means Abyai would be controlled by President Umar al-Bashir and Garang "as he will be vice president".
Expectations have been mounting the Sudanese government and the SPLA will soon sign a comprehensive peace deal after a key wealth-sharing agreement was signed earlier this month.
Talks have been ongoing about power-sharing and the status of three disputed regions.
While agreement has nearly been reached on the central Nuba mountains and southern Blue Nile State, according to negotiators, there had been little progress on resolving the status of the Abyai district.
The SPLA has been at war with Khartoum since 1983 and the conflict has claimed more than 1.5 million lives and displaced some four million people.
Wealth and resources have played a key role in the war and have come to overshadow its ethnic, religious and political roots.