Nor-West Taxis owner Paul Boler has never charged anyone to use a credit card and said the impact was minimal. "Ten per cent seems huge. I don't think credit card companies charge that."
Retailers are typically charged 1.5 per cent to 2 per cent for every credit-card transaction. Mobile credit card facilities can be slightly more expensive.
The Commerce Commission is surveying more than 3000 businesses to see if surcharges are being used fairly. They have been allowed since 2009, when the commission struck an agreement with credit-card companies Visa and MasterCard. That deal allowed retailers to recover banks' merchant fees by charging extra on customers' credit card payments.
The agreement was intended to enable retailers to charge customers less for goods and services. But commentators say that hasn't happened and say some companies use them to feather their nests.
Pramen Singh, who runs TaxC Service, with just two full-time drivers, said: "I'm not here to rip people off."
A Commerce Commission spokeswoman would not speculate on whether the taxi surcharges were excessive but said any explanation about the reason for the charges must not be misleading.
Alert Group chief executive Tim Simpkins did not want to comment.
• Readers have been contacting us with names of companies charging excessive surcharges. We've compiled a list on the Herald on Sunday Facebook page. To add to the list, comment on Facebook or email susan.edmunds@heraldonsunday.co.nz.