The bank today said that it was anticipating problems due to Microsoft's decision to bundle pop-up blocking software in the long anticipated security upgrade.
A spokesperson for St.George today said that the bank had tested the service pack and found that it would cripple the login process for its online banking service.
"It was found that the biggest issue customers will face is with the Internet Explorer pop-up blocker. As the pop-up blocker is automatically turned on, customers wanting to access Internet banking will have this page blocked," said the spokesperson.
Pop-up windows are a common annoyance for Web users. Web designers often program the windows to spawn from their sites automatically in response to innocuous user behaviour such as clicking on links or images.
The windows commonly carry Web promotional material, artificially inflate page impressions and prevent users closing a particular page, but in some cases they have been known to contain malicious code that can force PCs to download Trojans and viruses.
However, St.George -- and apparently other banks -- incorporate pop-up windows into the authentication process for their online banking service.
St.George today said it would provide extra support information for its customers instructing them on how to disable the pop-up blocker, but it also hinted that it may make more dramatic changes to the site.
"We are also currently reviewing the logon process to help minimise the impact the pop up blocker causes," said the spokesperson.
ZDNet Australia contacted a number of other banks for comment on this report but they were unable to respond in time for publication.