It also warns that similar dynamics are starting to emerge with debit cards, with contactless and online debit card use rising from 2 per cent of transactions two years ago to 15 per cent today.
It estimates that fees to merchants could rise by $216 million a year if contactless transactions rise to 60 per cent of debit payments.
Smaller merchants are also paying more, the report says. "There appears to be systemically higher costs placed on smaller merchants to pay for the processing of retail transactions." Interchange fees are sometimes two-and-a-half times the rates for the largest merchants.
The paper, which is out for consultation, says the ministry believes further investigation is needed into the costs and benefits of regulating interchange fees on credit card transactions.
It also proposes looking at whether eftpos, which doesn't charge fees, can be made into a sustainable alternative to debit products and whether the entire system should be viewed as a utility.
Industry lobby group, Retail NZ, welcomed the paper. "Fees in New Zealand are continuing to increase, while in other comparable jurisdictions, they are going down over time," said Greg Harford, general manager public affairs.
"Costs are rising rapidly as customers increasingly transition from traditional eftpos to contactless debit transactions."
Karen Scott-Howman, chief executive of the Bankers' Association of New Zealand took issue with the report's assumptions.
"It's not correct to say that businesses will always pass on merchant service fees to consumers through the price of goods and services.
"It's up to individual businesses to decide how they set their prices and there are likely to be many factors they will consider."