Walmart Canada stores will stop accepting Visa Inc. cards as the credit card provider charges merchants "unacceptably high" fees, the retailer said on Saturday.

Walmart has been unable to agree with Visa on an "acceptable fee," and will no longer accept the company's credit cards starting July 18, it said in a statement.

The move will not affect the U.S. stores of parent Wal-Mart Stores Inc.

A Visa spokeswoman said in a statement it offers "one of the lowest rates available to any merchant in the country" and said Walmart Canada's decision will have a negative impact on shoppers.

Representatives of Walmart Canada and Visa declined to address questions on specifics of payment terms.

A Walmart Canada spokesman said the retailer pays more than C$100 million ($78.27 million) in credit card fees every year, but specific transaction fees are part of "confidential agreements."

Canadian retailers have long complained about what they call the high interchange fees they pay credit card companies.

In 2014 Visa and MasterCard Inc said they would trim Canadian transaction rates to an average effective rate of 1.5 percent, after complaints about their fees almost resulted in government intervention.

Unlike American Express Co, which typically negotiates a flat fee with every merchant, Visa and MasterCard have variable fees based on the status of their different cards.

Small retailers, which usually have less power to negotiate transaction terms, have said that hurts them as they are never sure of the exact rate they will be billed between 1 percent and 3 percent on any given transaction.

Walmart Canada said stores in Thunder Bay in the northwestern part of the Ontario province will be the first to stop accepting Visa cards, and the change will then be rolled out "in phases" to the rest of the more than 370 Canadian Walmart stores.