Visa has entered the contactless payments pricing war that erupted earlier this year between Mastercard and Eftpos Australia.From 20 July Visa will lower the interchange fees levied on merchants when debit card users make over-the-counter purchases.The fee, which currently stands at a flat rate of 6.6 cents, will be lowered to a flat rate of 5.5 cents.The reduced fee will apply to both contactless and  "swipe and pin" debit card purchases that are processed through Visa's settlements platform.This brings Visa's interchange pricing into line with that of Mastercard for over-the-counter purchases(otherwise known as "card present transactions").Mastercard announced changes to its debit interchange rates in early April, which saw its interchange fee on contactless debit transactions slashed from 12 cents to a flat rate of 5.5 cents per card purchase.Eftpos Australia currently collects a standard interchange fee of 6 cents per transaction but Banking Day understands this pricing is under review.The lowering of interchange fees for over-the-counter debit transactions should result in some reduction to the overall costs borne by retailers for accepting debit card payments.However, the interchange fee represents only a fraction of the total service fees that merchants cough up to the banks for accepting debit card payments.Neither Visa nor Mastercard disclose publicly the value of so-called "scheme fees" that are paid by banks and are then passed on to merchants.The lowering of interchange fees by the global card schemes appears to be a corollary of RBA moves in the last two years to open the processing of contactless payments to competition.ANZ and Westpac have begun to roll out new services that allow merchants to choose whether contactless debit payments are processed by Eftpos or one of the global schemes.Quarterly data published by the central bank's payments department indicate that Visa and Mastercard have reduced total average fees paid by merchants on debit transactions since Tyro introduced merchant choice routing early last year.According to the RBA, the average merchant fee paid by retailers in the March quarter for processing debit transactions through Visa or Mastercard was 0.52 per cent - down from 0.59 per cent a year earlier.However, Eftpos remains the cheapest processing platform, with the RBA reporting its average total merchant fee at 0.26 per cent.Russell Zimmerman, the chief executive of the Australian Retailers Association, said his members were hopeful that NAB and CBA - the country's largest distributors of merchant terminals - would soon launch new routing services."We're hopeful that we will soon hear announcements from those two banks," said Zimmerman."And we would like to think that the services they plan to offer will be closer to the automated least cost routing that the Reserve Bank has recommended."That's what the RBA asked for and that's what we expect them to do."Under the new pricing arrangements to take effect on 20 July, Visa has also adjusted interchange fees for online retailers accepting payments by debit card.The interchange fee for online (otherwise known as card-not-present transactions) will shift from a rate of 6.6 cents per transaction to 0.22 per