There has been a call for credit card companies which operate here to be scrutinised for the levies they charge companies, which are then passed on to customers.
Last month, a £19 billion pound (NZ$35b) class action suit was filed against Mastercard in the UK over excessive interchange fees.
New Zealand First leader Winston Peters wants the same to happen here.
He told Mike Hosking everyone who's involved in overcharging should be investigated as to whether or not it's fair.
"It's actually not fair for them to charge what they like just because they might say certain charges are applicable, without denoting or specifying what those charges are."
Peters said authorities here are sitting on their hands when it comes to the issue.
Retail NZ said it has significant concerns about the level of merchant service fees charged by banks when customers use their cards.
"The issue is broader than interchange. Every time a customer uses a credit card or a contactless debit, the merchant has to pay a fee to their bank," Retail NZ said in a statement.
"The fees charged in New Zealand are significantly higher than those charged in the UK and Australia - where governments have regulated interchange rates.
"In New Zealand, merchants pay an average 1.7% for credit transactions compared to 0.89 per cent in the UK and 0.78 per cent in Australia. For contactless debit, Kiwi merchants pay, on average, 1.0 per cent, compared to 0.36 per cent in the UK and 9 cents per transaction in Australia (irrespective of the value).
"Overseas, rates are trending down over time, while in New Zealand, they are going up."
Retail NZ wants to see an introduction of more oversight and transparency through an information disclosure regime about merchant service fees and costs of providing services.
"While some merchants surcharge to recover the merchant service fees, this is not typical of retailers. Most retailers operate in a highly competitive environment and it mostly doesn't make sense to surcharge.
"Effectively, in the retail world, merchant service fees are a hidden cost that ultimately gets passed on to consumers. Other merchants (for example, in ticketing and travel) find it easier to apply a surcharge for card payments."
- additional reporting from Tamsyn Parker.