The Sudan consortium has met yearly since a 2005 north-south peace deal ended Africa's longest civil war. It is the stage for richer nations to show their support for maintaining peace in Sudan by pledging development funds.

But south Sudan's semi-autonomous government says it has received far less than donors pledged in the past, while funds earmarked for development have been diverted to aid for Darfur, where civil war erupted five years ago.

The report to the consortium, put together by the Khartoum government in conjunction with south Sudan's administration, said Sudan needed $6.1 billion for development over the next three years -- not including $2 billion in humanitarian aid.

The meeting is taking place from Monday to Wednesday in Oslo.

In the report, south Sudan's government said it had received only $550 million of the $4.1 billion pledged by donors following the peace accord in 2005.

South Sudan, one of the poorest areas on earth after being embroiled in civil wars on and off since 1955, has the world's highest maternal mortality rate and lowest rate of primary school enrolment, according to U.N. figures.

South Sudan said the delay in getting donor funds had set back the building of roads and other infrastructure and its ability to meet healthcare needs.

It blamed the World Bank-led mechanism on spending the money, known as the Multi-Donor Trust Fund (MDTF).

"The Multi Donor Trust Fund for southern Sudan took quite some time to become fully operational and by the end of 2007 had only spent 25 percent of the $350 million it had received from donors," it said.

The rest of the donor funds came in bilateral projects, many of which south Sudan's government was not aware of and had not approved, it added.

Much of the donor cash was diverted to the western Darfur region, where a conflict not covered by the 2005 peace deal has raged for five years between the Khartoum government and Darfuris who complain of discrimination and marginalisation.

The world's largest humanitarian operation in Darfur costs almost $1 billion a year not including the world's largest U.N.-funded peacekeeping operation which will consist of 26,000 police and troops once fully deployed.

With such an international focus on Darfur, a conflict Washington has labelled genocide, some campaigners worry the south Sudan peace deal is being neglected and implementation has fallen far behind schedule.

"Lack of attention to the implementation of the north-south peace agreement in Sudan is short-sighted and counter-productive," advocacy group Refugees International said in a statement on Monday.

"If the north-south peace agreement does not hold, there will be little prospect of achieving peace in Darfur."