A Nissan Motor Co. manual tells workers how to contact management if Transport Ministry officials show up for unannounced inspections and also instructs them to essentially hide information from inspectors.

But Nissan officials on Friday said the manual is not intended as a coverup tool.

News that the manual -- which deals with inspections regarding automobile recalls and repair services -- exists comes after Mitsubishi Motors Corp. made headlines this past summer for covering up customer complaints for more than 30 years.

The manual "was produced with the aim of having the inspections go smoothly," a Nissan official claimed. "While the expressions used (in the document) are unrefined, it is not intended to be a coverup."

A Transport Ministry official acknowledged that the automaker has told the ministry about the document's existence and indicated that the ministry will investigate the matter.

The ministry has also filed a criminal complaint.

"We do not believe there is anything contradictory in Nissan's explanation," the official said. "But we will look into whether it was indeed intended for covering up claims."

Nissan said it prepared the three-page document in spring 1998 when the ministry switched from announced to unannounced inspections.

It describes how to contact officials inside the firm when ministry officials show up for inspections and includes instructions such as "put away confidential documents" and "switch (personal computer) screens to 'inspection' mode."

"As such an unannounced inspection takes place in the midst of our ordinary business operations, we compiled the manual to properly keep confidential documents," a Nissan official said. "The wording in the manual is a bit rough as we did not intend it for external use."