Prime Minister Nouri al-Maliki has called on Kurdish authorities in the north of Iraq to hand over Vice-President Tariq al-Hashemi, who is accused of links to terrorism.
A warrant for his arrest was issued on Monday, a day after US troops pulled out of Iraq.
Mr Hashemi, a Sunni Muslim who denies the accusations, is currently in Irbil, under the protection of the Kurdistan regional government. His political bloc is boycotting parliament and the cabinet.
Mr al-Maliki says Mr al-Hashimi has to face justice.
''We gave Saddam a fair trial, and we will give Hashemi a fair trial too,'' he says.
Mr al-Hashimi told reporters in Irbil on Tuesday that he would be willing to face trial in Kurdistan.
''I swear to God that I never committed a sin when it comes to Iraqi blood,'' he said.