Commonwealth Bank of Australia (CBA) and Bank of Queensland (BoQ) have both been hit by systems failures this week, according to press reports.
CBA's software provider Oracle is reportedly working to fix a glitch that has caused "extensive problems" with the bank's CommSee teller system and online business banking application CommBiz.
The glitch, which occured after a routine upgrade of the Oracle platform, has resulted in delays for retail customers getting loan approvals and opening new accounts at branches.
According to press reports Oracle was forced to fly software experts into the country to help fix the problem.
CBA has told its buisness customers to avoid using the CommBiz platform until the problem has been fixed.
Meanwhile BoQ has been working to fix technical problems with its Internet banking service this week that prevented some customers from accessing their accounts.
The problem, which follows recent routine upgrades to the system, has left the bank's online services congested and unable to operate at full capacity at peak times.
Reports say BoQ is now shutting down the online service for 20 minutes at a time during peak hours to enable staff to reduce backlogs.
BoQ group executive and CIO Iain Blacklaw told reporters that the bank's tech staff are working overtime to fix the problem and hoped to resolve the issue over the weekend.