Retailers being asked for refunds due to cancellations from COVID-19 are being offered fraud detection technology to spot dodgy claims.
Mastercard is offering customers free use of its fraud and dispute resolution service, Ethoca, until July 31.
Aussie retailers using the service have received almost 40,000 alerts of possible fraud, amounting to $13 million, since August.
The alerts system shares data with banks, credit providers and retail groups to detect disputes.
Mastercard said disputes could often take retailers weeks to resolve, while the Ethoca technology could do it in days or sooner.
Mastercard Australasia president Richard Wormald said the impact of chargeback and fraud problems were greater for business at this time of economic uncertainty.
Mastercard acquired the Ethoca technology last year.
Credit card providers such as Mastercard are facing a new generation of competitors, led by Australian firm Afterpay, that provide customers credit without the need for cards.