The probe follows irregularities uncovered in the U.N. Procurement Service by the U.N. Office for Internal Oversight Services and the U.N. appointed Independent Inquiry Commission headed by former U.S. Federal Reserve Chairman Paul Volcker.
The investigation will be conducted by a not-yet-named external consulting company, but Annan's Spokesman Stephane Dujarric said Monday the review is expected to be completed by the end of September. Dujarric added Annan has appointed the U.N. Controller, Warren Sachs, to direct oversight of the UNPS, pending the investigation.
At the same time the OIOS is continuing its investigations into its former procurement officer, Alexander Yakovlev.
Yakovlev pleaded guilty earlier this month in federal court in New York to conspiracy, wire fraud, money laundering and taking bribes.