Westpac has warned customers of delays caused by its payment processing systems overnight.
The bank said this morning it had experienced "difficulties" processing payments "to and from other banks".
"Westpac customers can continue to make payments throughout the day which will be processed, however there will be some delays," a bank spokesman tweeted.
The spokesman said that Westpac customers would not incur fees as a result of the delayed processing of payments.
It was unclear how many customers were affected although at least one report pegged the figure in the "thousands".
The bank's spokesman could not say when the problems would be fixed.
It was the latest in a string of IT issues the Bank had faced. In May, a data centre blackout led to services being offline for hours to a whole day.