NAB did not mention which exchanges were blacklisted, saying only that it was introducing blocks to cryptocurrency platforms "where scams are most prevalent."
Crypto scams are one of the fastest growing security threats, with Australians losing more than $221 million last year.
According to the Australian Competition and Consumer Commission, Australians reported 3,910 crypto scam incidents in 2022, with an average victim forfeited of $56,600.
Nearly 50 percent of the scam funds reported to the Australian Financial Crimes Exchange were tied to cryptocurrency in a recent 30-day period.
"These scammers are part of organized transnational criminal groups," said Chris Sheehan, NAB's principal fraud investigator.
"Increasingly, we see them using cryptocurrency platforms to send stolen funds quickly and frequently abroad."
Crypto scams accounted for 7.1 percent of the total $3.1 billion in scams reported in Australia last year, the ACCC reported.
In June, Commonwealth Bank limited transfers to high-risk crypto exchanges.
That followed Westpac's decision in May to bar clients from transacting with Dubai-based Binance, the world's largest exchange.
Beyond the crypto scams, NAB said it had tapped into more than $270 million worth of customer payments, raising concerns between March and July.
9news.com.au has contacted NAB for comment.
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