A US-led effort to supply spare parts to the Afghan army is plagued by waste and potential fraud because of Kabul's shoddy record-keeping, according to a report issued Wednesday.

Much of the $370 million spent by the United States and its allies on spare parts for Afghan National Army (ANA) vehicles between 2004 to 2012 "cannot be accounted for," said a report from the Special Inspector General for Afghanistan Reconstruction.

The US-led Combined Security Transition Command relies on the Afghan army to maintain accurate inventory records but the Afghans have failed to keep an up-to-date tally on what parts are in stock, what parts have been ordered and when those parts are scheduled to arrive, the report said.

The audit found no documentation confirming that spare parts were delivered to the Afghan army from 2010 to 2012, it said.

As a result, the transition command's "current process for managing vehicle spare parts purchases leaves US-purchased equipment and funds vulnerable to waste, fraud, and abuse," the report said.

The audit follows a series of sharply critical reports from the special inspector general's office on the US aid effort to Afghanistan, including a scathing account of a $34 million facility built for the US Marine Corps that will probably never be used.

The United States has approved more than $95 billion in aid to Afghanistan since the Taliban regime was ousted in a US-led invasion in 2001.

The inspector general's team visited four spare part depots across the country and found that the Afghan army "did not keep fully accurate records at any of the four locations," the report said.

"Moreover, the ANA continues to place orders for vehicle spare parts without demand or usage data," it added.

The report included photos of boxes of vehicle spare parts that have not been registered in the army's inventory, piled up at warehouses in Afghanistan.

The security transition command, which is run by the NATO-led coalition in Afghanistan, had requested the audit after finding that it could not account for $230 million worth of spare parts.

The command accepted the audit's findings and now plans to redirect all spare parts to a US "transfer point" before handing them over to Afghan forces. It also is "attempting to repossess vehicle spare parts until the ANA can conduct an official inventory and transfer," the report said.

The NATO training mission in Afghanistan said it had introduced measures to better track spare parts and to ensure Afghan army vehicles are ready as coalition combat forces withdraw over the next year.

"As part of this transition process, we are facilitating a culture change within the ANA, helping to assure compliance with inventory management processes that will help ensure ANA mission success," Major General Dean Milner, deputy commanding general of the training mission, said in a statement.