Tensions have been building up between the government in Khartoum and the northern wing of the SPLM since South Sudan became independent in July as agreed under a 2005 peace deal.
The SPLM is the ruling party in the South, and the organisation split into north and south along with the country itself. The northern wing, SPLM-N, is allied to armed groups fighting the army in the poorly-marked border area. SPLM-N officials say its offices have been closed since violence broke out in the northern border state of Blue Nile earlier this month.
Sudan has asked the 17 parties to stop their activities “because their leadership and most members have lost the Sudanese citizenship,” the Council for Political Parties said in a statement. All parties were active in the South, it added.
Apart from the SPLM-N, 16 other parties affiliated to South Sudan were affected, among them the SPLM for Democratic Change which broke off from the SPLM and is now a major opposition party in South Sudan.
Government officials have said the SPLM-N is illegal because it is not registered as political party.
Sudan has recognised South Sudan as independent state but tensions have built up over unresolved issues such as violence in Blue Nile and South Kordofan states, sharing oil revenues and finding a solution for the disputed area of Abyei.
A day before southern independence on July 9, Sudan suspended six newspapers because southerners were among its owners or publishers.
Sudan’s north-south civil war which ended in 2005 after decades of fighting over differences over religion, ethnicity, ideology and oil, cost about 2 million lives.