Aljazeera early on Wednesday quoted Turabi's wife Wissal al-Mahdi as saying "many security men" surrounded the home of the head of the Popular Congress (PC) and arrested the 71-year-old opposition leader.
A former leading light of Umar al-Bashir's government, Turabi had been freed in October 2003 after spending nearly three years under house arrest.
His wife added that several leading members of the Popular Congress (PC) had also been picked up.
The move came after the arrest on Sunday of some 10 Sudanese army officers on suspicion of involvement in a military coup attempt apparently related to the ongoing conflict in west Sudan's Darfur region.
The officers arrested were thought to belong to the PC, which on Monday said that there had been a government crackdown on senior party officials following allegations of a coup attempt from within the army.
PC deputy leader Abd Allah Hassan Ahmad was summoned by security police on Sunday night and told some civilians also took part in the alleged coup attempt, a party statement said.
The authorities then launched a wave of arrests against party officials and axed or transferred a raft of officers in the army, police and security services who originated from Darfur, it said.
The PC denies backing the
rebel movement in Darfur
The accusations of Darfuri involvement in a coup attempt were a pretext for "a crushing military campaign against the people of Darfur," the party said.
In a statement, a PC official on Tuesday accused the Sudanese authorities of having invented the story of a coup so as to dissolve Turabi's party.
Turabi on Tuesday said that six party officials, including three politburo members, had been detained.
He linked the crackdown to government charges that his party supported the year-old rebel movement among Darfur's indigenous non-Arab minorities, an allegation he vigorously denied.