SYDNEY, May 18 (Reuters) - The Australian arm of Binance, the world's largest crypto-currency exchange, on Thursday said some customers there will be unable to deposit or withdraw money after a third-party service provider cut off its service.

Binance said on social media that users would be unable to make Australian dollar deposits by bank transfer with immediate effect after payments provider Cuscal cut access. Withdrawals would also be cut off, it said, without detailing when.

"We are working hard to find an alternative provider to continue offering AUD deposits and withdrawals to our users," Binance said in a statement.

Cuscal did not immediately respond to a request for comment.

The Australian Financial Review separately reported Westpac Banking Corp (WBC.AX), the country's second-largest retail bank, banned customers from transacting with Binance.

Westpac was not immediately available to comment when contacted by Reuters.

It said in an earlier statement that it had blocked some crypto-currency payments to reduce losses due to scams. It did not identify exchanges nor provide any further details.

The curb is the second blow to Binance's Australian operation in as many months, having relinquished a financial services licence in April amid a regulatory investigation.

Binance is battling regulatory suits and investigations around the world.

In March, the U.S. Commodities Futures Trading Commission (CFTC) sued Binance and its founder, Changpeng Zhao, for operating what the regulator alleged was an "illegal" exchange.

Customers can still transact using credit or debit cards, Binance said.

Reporting by Lewis Jackson and Byron Kaye in Sydney; Editing by Christopher Cushing

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