ANZ has performed poorly for the second month in a row in a benchmark of Australian banking websites.
The June benchmark, conducted by Compuware-owned web performance division Gomez between June 1 and June 30, shows ANZ's website availability at 99.58 percent.
A 99.58 percent availability rating equates to over three hours of downtime during the month.
The figure is well below the average of 99.93 percent, but a slight improvement on ANZ's performance last month, which came in at 99.48 percent.
The result puts ANZ last in the group of 14 bank websites measured. Eight of the 14, including ANZ's major bank competitors, achieved a 100 percent availability score during the month.
The result comes on the back of two serious outages that affected ANZ customers last month, including a near two hour outage of Internet banking and ATMs on June 22 and an Internet and telephone banking outage on June 16 that was blamed on "disk failure".
Sources close to the bank said it has under-invested in its internet banking platform in recent years, which has created capacity issues. It is understood the bank now has a team of people working on a project dedicated to addressing the ongoing problems.
A spokesperson for ANZ told iTnews the bank is continuing to invest in both the functionality and usability of its website.
"We have an ongoing program of improvements which will assist the experience of customers using anz.com" she said.
Compuware said there was an improvement in bank website response times last month, with nine of the 14 banks measured loading their home pages in less than two seconds.
"If it takes more than two seconds to get an online response, customers get frustrated" said Rafi Katanasho, solutions director of applications performance management with Compuware.
Last month Rabobank direct banking arm RaboDirect questioned the measurement process, after it changed its name and website address in May and received a response time score of 16.54 seconds, well outside the average of 3.11 seconds.
In June, the response time for RaboDirect came in at 11.43 seconds, an improvement, but still leaving the bank ranked last for response time.
A spokesman for RaboDirect said today that its own tests - using the same tools - continually record response times closer to three or four seconds.
The bank reiterated that Compuware's test is limited to using Microsoft's Internet Explorer 7 browser and thus "not representative when it comes to browser choice".