Garang, who led southern rebels in a civil war that lasted more than two decades, signed a peace deal in January and died just three weeks after becoming first vice president as part of the peace accord.
News of his death led to charges of foul play among the large southern community in Khartoum and sparked three days of riots that killed 111 people and injured more than 300, the worst violence in the capital in decades.
Garang was buried amid emotional scenes in Juba, the southern capital, on Saturday as President Omar Hassan al-Bashir promised mourners he would push on with the peace plan and soldiers of both sides carried the coffin in a show of unity.
The southern civil war, which claimed 2 million lives, broadly pitted the Khartoum-based Islamist government against the mostly Christian and animist south, complicated by issues of oil, ethnicity and ideology.
The peace deal, which ended Africa’s longest war, provides a new coalition government, wealth and power sharing, democratic elections and a southern referendum on secession from the north within six years.
It does not cover a separate conflict in the country’s western Darfur region, which has killed tens of thousands and forced more than 2 million from their homes.