News reports like this one in ITNews for Australian Business say that a server patch on Monday evening severely degraded the online banking service of Australia's Westpac bank for about 9 hours yesterday.
The patch, ITNews reports, caused the online bank web page to load too slowly for about 75% of Westpac retail customers from 0730 to 1630 local time. Back up processes kept the problem from affecting business customers and 25% of its retail customers.
Westpac is one of Australia's biggest banks, and its problem follows right on the heels of the system outage problem at the Commonwealth Bank of Australia that was caused by a security upgrade.
In related news, last Friday afternoon beginning at 1325 EDST, Bank of America, the largest bank in the US, also suffered an online banking outage that lasted approximately 4 hours. However, BoA has yet to say what happened other than calling it a "temporary system" issue.