The Sudanese government announced that oil began to flow through pipelines extending to Port Sudan in early April.
South Sudan gained control over the bulk of the region's oil reserves when it gained independence from Sudan in 2011. Sudan controls the exports pipelines, however, and disputes over transit fees prompted the South Sudanese government to halt oil production in 2012. South Sudan gets nearly all of its revenue from oil.
The Sudanese government is expecting $3 billion in compensation over three years from South Sudan for oil revenue lost from secession.
IMF envoy to Sudan Paul Jenkins told Bloomberg News the Sudanese government should think wisely about that money.
"Given the temporary nature of some of these revenues for Sudan, it is critical that they be used wisely to support reforms that will put the economy on a sound long-term footing," he said.
Sudan's economy contracted more than 4 percent last year.
This week, the Sudanese and South Sudanese governments agreed to set up border-crossing points near the oil-rich region of Heglig to connect Sudan's state of South Kordofan to South Sudan's Unity.
Disputes over Heglig nearly pushed both sides to war last year.