Sudan's new government of national unity will need up to $7.8 billion to rebuild its infrastructure and industrial installations damaged by the 21-year war.
According to Minister for Humanitarian Affairs Ibrahim Mahmoud Hamid, the dawning of a new era in Sudan, which was marked last Saturday, has come with heavy challenges.
"We are celebrating the peace, but a hard task remains. We have to rebuild the destroyed countryside and maintain the trust and faith needed to sustain the peace," he told reporters in Khartoum before the swearing in of Dr John Garang on Saturday.
Mr Hamid said the country would have to rely on donors to rebuild what has been destroyed by the war, especially in the southern part of the country.
But the country was in a festive mood as the power sharing agreed upon between south Sudanese and the government of President Omar Al-Bashir became a reality.
After 22 years of armed rebellion, Sudanese People's Liberation Movement (SPLM) leader John Garang finally crossed the floor to take up his new position as Al-Bashir's principal deputy in a deal that saw all his senior officers allocated Cabinet posts.
In total, 100 Sudan People's Liberation Movement SPLM delegates will be nominated as MPs in a temporary arrangement as the structure of the new government, to be in power for six years, is worked out.
A transitional constitution that legalised the new government was speedily discussed and ratified by MPs in an exercise supervised by close aides of the two leaders.
The Constitution, signed by President Al-Bashir last Thursday, gives Dr Garang's SPLM 28 per cent of the 30 Cabinet posts. The government will take 52 per cent while other parties in the south and north of the country will get six and 14 per cent respectively.
It takes the country of 36 million people to full federalism with each state being autonomous. But militia groups still holding out in the south and the east of the country have cast a shadow over the new government.
On his way to Khartoum for the swearing-in ceremony, SPLM spokesman Samson Kwaje told The EastAfrican last Thursday, "Judging from what has happened since the signing of the peace agreement in January, we are optimistic that its provisions will be respected and implemented to the letter."
He said his optimism was based on reports from the 100-member SPLM advance party to Khartoum, which indicated that the government of President Omar El-Bashir is co-operating fully with its new partners.
Dr Garang, who returned to Khartoum last Friday for the first time in 22 years, was accompanied by a 200-strong delegation.
Prior to the formal constitution of the government of national unity, which will include the SPLM and other southern Sudanese parties, President El-Bashir on Thursday signed into law a new Constitution that will, among other things, open the presidency to competition by both Muslims and Christians. It is the first Sudanese charter to recognise freedoms of religion and expression as fundamental human rights.
Sudanese MPs had early in the week approved the constitution, making Sudan a presidential republic, where El-Bashir stays as the president, with Dr Garang becoming president of south Sudan and first vice president.
Former first vice-president Ali Osman Taha, who led the government side in the protracted peace negotiations, now becomes the second vice president.
The constitution, which was specially written to cater for the Comprehensive Peace Agreement signed in January 9 in Nairobi between the SPLM and President El-Bashir's ruling National Congress Party (NCP), will govern the country for the six-year transition period, after which the southerners will vote in a referendum to decide whether to remain part of larger Sudan or opt for a separate existence.
Of great pleasure to the SPLM, according to Dr Kwaje, is that the southerners will for the first time get more Cabinet posts, as opposed to the past, when the south used to get a maximum of three posts.
The constitution stipulates that general elections will be held four years into the interim period and that prospective contenders must first endorse the agreement.
Dr Kwaje is confident that SPLM will bag at least 10 full ministerial positions and 11 assistant ministers.
By joining the government, Dr Kwaje said he hoped that the SPLM will inject new ideas in the way the country is governed, especially to help change attitudes to the concept of power-sharing and decentralisation of power. He is also optimistic that the SPLM will help put pressure on the government to settle the Darfur issue as soon as possible.
Already, the Khartoum govern-ment has lifted the ban on Popular Congress Party of ally-turned-foe Hassan Turabi, an Islamist opposition leader who has been under house arrest since March 2004.
Other positive signs, are the lifting of the state of emergency in northern and southern Sudan and the release of political prisoners, among them hundreds of SPLA soldiers.
The SPLA took up arms demanding more autonomy for the south in 1983 in protest against discrimination and the imposition of Islamic Sharia laws, in a war that left some two million people dead and about four million displaced.
Besides Darfur, several armed groups in the south and east are yet to sign on to the Comprehensive Peace Agreement and will not be represented in the government of national unity.
The challenge now for President El-Bashir is to incorporate those who still retain some grievances, and specifically to convince the southerners - who have been complaining of discrimination - that they belong to the larger Sudan.
As it is, most southerners are still keen on voting for a separate state after the six-year interim period, while the northerners are keen to have a united Sudan.
Dr Garang, for instance, has stated that whether the south will remain in the larger Sudan will depend on the speedy reconstruction and rehabilitation of the war-torn south in a manner that will convince southern residents that they are at par with the north in terms of infrastructure.
The southerners, though, retain a quasi-autonomous state, with a semi-autonomous government and legislature, its own army, national anthem, a flag, a separate banking system and judiciary. The south also has its own constitution, set of laws and educational system.