TOKYO -- Japan's antitrust authority is investigating Visa's Japanese unit for allegedly pressuring card companies to exclusively use its credit information system, a practice potentially hindering competition and harming consumers, local media reported on Wednesday.

The local unit of Visa, a major global credit card brand, is suspected of imposing higher fees on credit card companies that did not use its network for credit checks, thereby forcing them to abandon competitors' networks, national news agency Kyodo reported, citing sources close to the matter.

The Japan Fair Trade Commission (JFTC) inspected Visa Worldwide Japan Co.'s Tokyo office, suspecting violations of the country's antimonopoly law, which forbids dominant companies from enforcing unfair trading terms on weaker firms. Violations can result in cease-and-desist orders or penalties.

Visa's practice is likely aimed at excluding competitors from the market, which could keep fees high and increase the burden on consumers and shops that use the service, said the report.

Most Japanese credit card companies rely on networks operated by Visa or NTT Data Japan Corp. for credit information checks.

The JFTC is also examining Visa's Singaporean unit, which oversees Asia-Pacific operations, and investigating whether Visa's U.S. headquarters were involved.

In 2023, Japan's credit card transactions totaled approximately 105 trillion yen ($670 billion), data from the Japan Consumer Credit Association showed.