Iraq's judiciary issued arrest warrants at the beginning of March for four men, including a former finance minister and staff members of former prime minister Mustafa al-Kadhemi, who Baghdad says all live outside the country.

Haider Hanoun, the head of the Iraqi Commission for Integrity, on Sunday called on "competent authorities in the United States and the United Kingdom to cooperate in executing the arrest warrants issued against them", without specifying where the suspects are located.

He said in a statement that Interpol had issued Red Notices against Kadhemi's cabinet director Raed Jouhi and personal secretary Ahmed Najati, both of whom hold American citizenship.

Another Red Notice has been issued for former finance minister Ali Allawi, "who holds British citizenship," Hanoun added.

An Interpol Red Notice is not an international arrest warrant but asks authorities worldwide to provisionally detain people pending possible extradition or other legal actions.

The fourth suspect, the former premier's media adviser Mushrik Abbas, "currently resides in the United Arab Emirates," according to Hanoun, who said he did not know if Abbas held another nationality.

"We hope that they (London and Washington) will cooperate and extradite the suspects," said the official.

Allawi, a respected politician and academic, resigned in August last year. When the scandal broke a few months later, he denied all responsibility.

The case, which has been dubbed "the heist of the century", sparked outrage in oil-rich but corrpution-plagued Iraq.

At least $2.5 billion were stolen between September 2021 and August 2022 through 247 cheques that were cashed by five companies.

The money was then withdrawn in cash from the accounts of these companies, most of whose owners are on the run.

Kadhemi has previously defended his record on fighting corruption, saying his government had discovered the case, launched an investigation and taken legal action.

The four men are accused of "facilitating the embezzlement of sums belonging to the tax authorities".

The country's current Prime Minister Mohamed Shia al-Sudani has vowed to crack down on corruption since his appointment in late October.