"I reject this constitution which calls for sectarianism and there is nothing good in this constitution at all," he told Aljazeera late on Saturday.
He criticised federalism in the constitution, which is rejected by Iraq's Sunni Arabs, who fear it will give Kurds and Shias too much power and control over Iraq's oil resources.
"If there is a democratic government in Iraq, nobody has the right to call for the establishment of federalism anywhere in Iraq whether it is the south, north, middle or any other part of Iraq," he said.
Al-Sadr's remarks raised the possibility of a crisis over one of Iraq's most explosive issues.
AljazeeraLast Mod: 20 Eylül 2018, 18:16