Students held protests in the universities of Khartoum and Gezira in the north's agricultural heartland on Wednesday against proposed cuts in subsidies in petroleum products and sugar, a strategic commodity in Sudan.
The cuts come at a politically sensitive time for the government of President Omar Hassan Al-Bashir, who stands to lose control over the south in the referendum, agreed as part of a 2005 deal to end a north-south civil war.
Other prices have also risen due to a surge in global food prices and a devaluation in the local currency.
In Khartoum University, police beat dozens of students demonstrating against the price rises, with five slightly injured and an unknown number arrested, one student said.
"The security forces were already there with a very, very heavy presence," said journalism student Al-Fadil Ali.
"They fear this could lead to revolution."
Sheza Osman Omer from the opposition Democratic Unionist Party in Gezira said several people were injured in clashes between police and students protesting on the streets.
She said police beat them with canes and arrested three female students. The police spokesman was not immediately available to comment on the reports.