The Commission of Integrity anti-graft body, presided over by Judge Haider Hanoun, responded with a statement denouncing what it called slander and lies, and said the recordings had been "fabricated".

Corruption is endemic in Iraqi state institutions, with the top echelons of power often evading accountability.

It is not unknown in Iraq for public officials to try to settle scores by trading accusations.

One sound clip on social networks, which has been picked up by media outlets, appears to be from a conversation suggesting Hanoun had received large sums of money and even a luxury car.

AFP was unable to verify the authenticity of the recording.

"The attorney general has asked an investigating judge to examine audio recordings attributed to the acting director of the Commission of Integrity, Haider Hanoun, in relation to bribery offences," the judicial statement said.

The Commission of Integrity's own statement announced a press conference for Thursday to "expose the facts and deny these calumnies and inventions".

It denounced "electronic armies" which had "fabricated sound extracts attributed to the head of the authority", aimed at "dissuading him" from his mission and obstructing the commission's work.

At the beginning of September, Hanoun accused a judge of having obtained state land by posing as a security officer.

He made the accusation at a heated press conference in Iraq's autonomous northern region of Kurdistan as he defended his own ownership of two plots of land in the south of the country.

In late August, an Iraqi criminal court issued arrest warrants for a businessman and a former government official wanted over their alleged involvement in stealing $2.5 billion of public funds.

The scandal has been dubbed the "heist of the century" in Iraq.