The likely main donor, the United States, sent the State Department's second in command to Norway to attend a donors' conference that opened on Monday to mobilise funds for Sudan.
Robert Zoellick, a top deputy to Secretary of State Condoleezza Rice, is expected to announce at Oslo what Bush administration officials called "a significant pledge" for Sudan.
Sudan is seeking $2.7 billion in international aid for emergency reconstruction in southern and northern regions of the war-ravaged country.
Most of the money pledged will be used for reconstruction and development of the devastated southern region, where rebellion raged from 1983. Some will be spent on humanitarian aid, while a slice will go towards implementing the peace agreement signed in January.
Since 2003, Washington has given $1 billion in aid related to the North-South war and $600 million for the western region of Darfur, mostly for humanitarian relief.
Zoellick was to meet the Sudanese government and rebel leaders from the Sudan People's Liberation Movement while in Norway before heading to the country later in the week.
His trip is designed to encourage both sides to move more quickly on the peace deal they reached in January and then to pursue peace in Darfur.
Speaking at the conference, UN Secretary-General Kofi Annan warned that the peace agreement signed between the Sudanese government and the southern rebel movement could turn into new fighting unless the international community support the implementation of the peace accord.
"All the people of Sudan want clean water, food for their families, schools for their children, proper healthcare, and the prospect of development. They have earned this peace. We should not fail them," Annan told donors.
Zoellick is expected to announce
a significant pledge for Sudan
The agreement between the Sudanese government in Khartoum in the north and the rebels who control the south was intended to end the civil war that has claimed more than 2 million lives over two decades.
Washington says the two sides have fallen behind schedule on the agreement that lays out power and wealth-sharing rules and says the south Sudanese will determine whether they want their region to remain part of Africa's largest country after six years.
Bush administration officials worry that the peace agreement could unravel without strong international backing, and it could be derailed if the conflict persists in Darfur.
That conflict has killed tens of thousands of people and more than 2 million people have been uprooted since early 2003.
Canada has set aside $90 million to help support the peace effort in Sudan, International Cooperation Minister Aileen Caroll said at the Oslo conference.
Canada's pledge will be forthcoming in coming months and Ottawa hopes it will alleviate key humanitarian needs in Sudan, the minister said.
The UN estimates that $2.6 billion will be needed by the end of 2007 for reconstruction and development in southern Sudan.