An inquiry into the theft of some $900 million which led to the near-collapse of Afghanistan's largest bank has found there was high-level political interference over who should face prosecution.

"Information received during the inquiry indicates that the final decision about who to indict was made at the political level in the spring of 2011 by a high-ranking committee," the inquiry report said Wednesday.

"Prosecutors from the attorney general's office were called in to amend the indictment to conform to the decisions taken," said the report of the inquiry, funded by foreign donors.

Three Afghans and three foreigners sat on the Independent Joint Anti-corruption Monitoring and Evaluation Committee which conducted the investigation.

Afghanistan has put on trial nearly two dozen people accused of involvement in the fraud that pushed the nation's once-biggest private lender to the brink of collapse.

The 22 suspects include the bank's founder and chairman Sher Khan Farnoud and CEO Khalilullah Ferozi, who are accused of stealing hundreds of millions of dollars through off-book loans.

Among the bank's shareholders who took loans were a brother of President Hamid Karzai, Mahmood Karzai, and the brother of his vice president Marshal Mohammad Qasim Fahim. They have not been charged with any wrongdoing.

"The indictment did not include officials from accounting firms that created false documents for Kabul Bank, airline employees that smuggled money out of Afghanistan, or shareholders who received funds from loans at zero interest, apparently without the intention of repayment," the report said.

The trial, which is being handled by a special tribunal set up by Karzai earlier this year, is seen as a crucial test of the government's commitment to crack down on rampant corruption.

The scandal, which first broke in 2010, prompted the International Monetary Fund temporarily to suspend hundreds of millions of dollars of international aid to Afghanistan.

The government's handling of the case is being watched closely by Western countries which have pledged billions of dollars in aid after NATO troops withdraw in 2014 -- on condition corruption is brought under control.

Renamed New Kabul Bank, the institution was bailed out by the government after its former bosses failed to return $900 million they had allegedly taken in secret loans.