UniSuper's private cloud outage has been put down to an issue with Google Cloud.

The week-long systems outage at the Australian pension fund for the education and research sectors was caused by a "combination of rare issues at Google Cloud," Google Cloud said in a statement issued via UniSuper.

The company said that the issues resulted in an "inadvertent misconfiguration" during the provisioning of UniSuper's private cloud. This then led to a software bug that impacted the superannuation fund's secondary systems.

"This was an unprecedented occurrence, and measures have been taken to ensure this issue does not happen again,” the company added.

Google has reiterated that the problems were not caused by malicious behavior or cyberattacks.

UniSuper said: “Google Cloud is not the only cloud service provider UniSuper utilizes, and this planning has ensured our ability to restore services and minimize data loss."

The fund's CEO, Peter Chun, said on May 6 that restoration works would likely begin on Thursday this week, and that in the meantime, some services will be limited.

Chun added that member accounts are safe, and that pension payments have not been disrupted.

UniSuper moved a large amount of its workloads to Google Cloud Platform in 2023, having previously split them between Azure and two of its own data centers. The migration included the shifting of all non-production workloads, including 1,900 virtual machines, to Google Cloud.

The superannuation fund experienced an outage in 2017 after a fire in its Port Melbourne facility. The company also had a data center in Mitcham, Victoria.

The fund owns a five percent stake in Vantage Towers, having acquired the share in May 2023 for AU$1 billion (US$676.3m)