Ghosn, who has denied wrongdoing and has been freed on $4.5 million bail, is pursuing claims against Nissan and Mitsubishi Motors, who ousted him as chairman of their alliance after raising allegations of embezzlement.

"The request for legal assistance from Japan has been delegated to the Zurich public prosecutor's office for enforcement and is currently being processed," the office said, without giving any further detail on what it had been asked for.

"The Zurich public prosecutor's office is not conducting its own proceedings," it added.

(Reporting by John Miller; Editing by Alexander Smith)