"The road to peace has been long and uphill," Norwegian Prime Minister Kjell Magne Bondevik said, opening the two-day meeting.
"We count on you to lead the reconstruction of areas devastated by war. Your people deserve it. They have waited too long to return to Sudan and live in peace."
The meeting brings together donor countries, international organizations and former enemies in the conflict who have joined a transitional team to create a joint government.
Sudan hopes for pledges of EUR6 billion, said the Sudanese minister for international cooperation, Yusuf Suleiman Takana.
The conflict in southern Sudan was separate from the two years of bloodshed in the country's western Darfur region, where 180,000 people have died, according to U.N. estimates. In eastern Sudan , tribes and opposition activists have also clashed with government forces seeking greater rights and state assistance.
World Bank-administered funds would be launched at the conference for the new Government of National Unity in the Sudanese capital, Khartoum, and for the government of South Sudan , the Norwegian government said.
The peace treaty sets out power and wealth-sharing rules, and calls for a referendum in six years on whether the south will remain part of Africa's largest country.
In the north-south war, Islamic-dominated Khartoum fought rebels seeking greater autonomy and a greater share of the country's wealth for the Christian and animist south. The conflict is blamed for more than 2 million deaths, primarily from war-induced famine and disease.
Norway had an active role in the Sudan peace process, and was asked in April 2003 to host the international donors conference.
The conference has drawn representatives of the U.S. and Canada; many European countries, including Germany, the U.K., Russia and France; Asian powers Japan and China; and African and Arab nations. Major organizations were also represented, including the European Union and the World Bank.
Sudan 's delegation was led by two Sudanese vice presidents, Ali Osman Mohammed Taha and former rebel leader John Garang of the Sudan People's Liberation Movement.