"The bomb was placed in the car when Nida and his guards went to Tikrit early on Tuesday," Thabit al-Azzawi, a police colonel, told the AFP news agency.
"It exploded while they were on their way back."
Al-Neda was a member of the delegation representing Saddam's tribe which collected the ousted leader's body after his execution in December 2006 for burial in Awja.
In 2007, he founded a so-called Awakening Council in Saddam's home village of Ouja, working with US forces to fight Sunni armed groups in the area.
Members of Saddam's tribe have been targeted before, but it was unclear whether it was because of their ties to the former Iraqi leader or because of long-standing tribal rivalries.
Al-Neda's brother, Mahmoud al-Neda, was shot dead by unknown attackers in summer 2006.