Visa Australia has amended its card scheme regulations to allow banks to enforce the Reserve Bank's new card surcharging standard.On Friday, Visa said the new scheme rules were aimed at limiting the fees retailers can charge those customers paying with a debt or credit card.Under the Reserve Bank's new standard, merchants have a right to recover their card acceptance costs through a surcharge. The "reasonable cost of acceptance" includes the merchant service fee charged by the merchant's acquiring bank and some additional costs.The new standard takes effect today (March 18).Card scheme operators have the right to change their scheme rules to limit surcharging to a reasonable cost. So far, Visa is the only scheme operator to have announced changes to its rules.Vilpin Kalra, Visa's Australian country manager, said one-third of merchants accepting Visa card apply a surcharge. Of those, 99 per cent use the merchant service fee as their cost of acceptance.The chief executive of Tyro Payments, Jost Stollman, said about 100,000 companies impose some type of surcharge.Stollman has estimated the potential savings for consumers at A$350 million if all scheme operators follow Visa's lead and change their scheme rules to limit surcharging.Dealing with these merchants will be straightforward but it will be a more complex exercise working out a reasonable cost of acceptance for those merchants that choose to include additional costs.The RBA has listed additional costs under five headings: other costs payable to acquirers, including fees for the rental and maintenance of payment card terminals; costs payable to other payment system service providers, such as gateway and switching fees; merchants' own costs related to card acceptance, such as the purchase and maintenance of their own card acceptance infrastructure; fraud costs related to acceptance, such as equipment required to mitigate fraud; and any fixed equipment, systems or development costs not captured under the other headings.Kalra said Visa has developed some tools to helps merchants and their acquiring banks work through the process.Visa has also commissioned Deloitte to provide auditing services to merchants and their banks in complex cases or where there are disputes.Kalra said he expected the process to run smoothly but he is prepared to handle disagreements."We deal with negotiations every day over a range of things - chargebacks, fraud, settlements and online acceptance," he said.One of Visa's aims will be to bring the practice of blended surcharging to an end. Different scheme operators charge different merchant service fees but an increasingly common surcharging practice is to average out the fees and apply a blended surcharge rate.Visa and MasterCard have lower service fees than American Express and Diners Club for most of their cards and believe that a more transparent surcharging regime will be to their benefit.One of the key principles in Visa's new surcharging rules is that "consumers who receive a refund on a purchase also have the right to receive a refund of the surcharge amount."Kalra said: "Merchants who surcharge might not pay back the surcharge."