The Sydney Morning Herald is reporting that almost 100,000 Australian bank customers have had their details leaked in a cyber attack on real-time payment platform PayID.

The new platform, launched to much fanfare last year, allows the instant transfer of money between banks with just a mobile number if email address.

However, the attack on Westpac, which also affects customers from other banks, now has computer security experts worried that the data could be used for fraud.

Westpac confirmed the incident on Monday, saying “Westpac can confirm we had detected misuse of the [New Payments Platform’s] PayID functionality and we took additional preventative actions which did not include a system shutdown,” a spokesman said. “No customer bank account numbers were compromised as a result.

“There has been no further inappropriate activity detected.”