Around 60,000 enumerators, monitored by 200 observers, will count the estimated 40 million population, costing Sudan and the international community over $100m.
"So far everything is going smoothly," Ibrahim Abbas, head of the census in the north said.
"We are not predicting any problem either today or in the coming days".
But the underdeveloped south has refused to be bound by the results of the census.
Fighters in the country's western Darfur region are also boycotting the count, accusing the Arab north of manipulating the census to maximise its control and marginalise the African majority.
International observers have raised concerns that significant parts of Darfur, a region the size of France, will be excluded from the count owing to fierce opposition from rebel groups.
"Before peace there is no census," Khalil Ibrahim, the leader of the Justice and Equality Movement, the strongest military group in Darfur, said.
"My people are not there at home, many of them crossed borders. They're in Chad and concentrated in IDP camps, under trees here and there, in mountains and villages, so what they're doing is meaningless," he added.
The authorities claim that only three per cent of Darfur will be left out of the census but international observers believe that far more will be excluded.
|There are fears that refugees in Darfur will not |
be counted in the 2008 census [GALLO/GETTY]
Mohamed Ali Al Mardi, a former Sudanese justice minister, told Al Jazeera that the fact a census was being held was proof that the security situation in the war-torn region was improving.
And he said that UN figures on the death toll in Darfur due to violence, starvation and malnutrition wre inflated.
"The number of victims in Darfur has been exaggerated very much. A fortnight ago the number stood at 200,000 people. Now we hear of 300,000 people. This is a report that lacks credibility."
"The number as we know it from the local authorities and the tribal chiefs and the inhabitants of the villages stand at between 10,000 and 12,000 people. Not more than that."
But victims of a separate five-year conflict in Darfur have also rejected the census, saying they did not trust the government.
"No, no to the census," chanted protesting Darfuris in the region's most volatile Kalma camp.
The UN, advising the government in carrying out the census, says that while 34 per cent of Darfur camps and 19 per cent of localities were likely to be inaccessible because of security problems or a refusal to take part, they could still extrapolate their numbers using technical methods.
The census is highly politicised as Sudan's multiple civil wars have all been caused by marginalised regions demanding more rights from the central northern Nilotic tribes who have dominated power since independence from the British in 1956.
Religion, a question which was not included in the census angering the mostly Christian or animist southerners, also played a major role in the war.
Islamic Sharia law was imposed in Sudan in 1983 fuelling the north-south conflict. It was lifted in the south with the 2005 deal although southerners can still use Sharia courts if they wish.
With the peace deal aiming to hold elections by July 2009, the census was to be held in 2007 under the same accord.
Ban Ki-moon, the UN secretary-general, warned that further delay of the census "could have considerable political and financial implications".
The International Crisis Group has also warned that the electoral timetable is severely behind schedule.
The group has said that due to problems in Darfur the election will require a contingency plan or the entire electoral timetable will need to be reworked.