Japan's antitrust watchdog is set to issue a warning to Nissan Motor over allegations of underpaying subcontracted parts manufacturers, according to local media reports on Monday. The automaker is said to have unilaterally reduced payments to dozens of subcontractors upon delivery of parts.

The commission, as reported by public broadcaster NHK, will demand Nissan to take corrective measures to prevent such underpayments from recurring. While Nissan awaits the final report from the commission, the company has refrained from providing further comments on the ongoing investigation.

Nissan, however, acknowledged that it has already refunded the full amount of the upfront payment received from the supplier, a term the automaker uses to describe the unilaterally reduced funds. According to NHK, the commission's investigation revealed that Nissan had deducted a few percent from the predetermined delivery payment to parts manufacturers, including those producing tyres and wheels.

The practice, reported by Kyodo news agency to potentially span decades, could amount to about 3 billion yen (approximately $19.98 million) worth of unlawfully deducted payments over several years. Japan's Subcontractor Law prohibits ordering parties from unilaterally reducing payments when subcontractors are not at fault.

Nissan's response to the allegations and the antitrust watchdog's final decision are eagerly awaited as the issue unfolds in the automotive industry.