In an update issued on Monday, UniSuper chief executive Peter Chun said services that were expected to have online in some capacity would include the ability to login to online services, access Mobile App, and see balances — initially as at 29 April.

As regular trading and investments have been continuing as normal, this would be reflected in members' balances once systems had been restored, he added.

A Google Cloud spokesperson said the disruption of UniSuper services was caused by a combination of rare issues at Google Cloud that resulted in an inadvertent misconfiguration during the provisioning of UniSuper’s Private Cloud, which triggered a previously unknown software bug that impacted UniSuper’s secondary systems.

"Google Cloud sincerely apologises for the inconvenience this has caused, and we continue to work around the clock with UniSuper to fully remediate the situation, with the goal of progressively restoring services as soon as possible.

"We would like to stress again that this was an isolated incident and not the result of a malicious behavior or cyber-attack, and that no UniSuper data has been exposed to unauthorised parties."

Chun added: "To minimise further disruption to our members as we come back online, we are putting on additional resources to work through all inquiries and member requests as quickly as possible once systems are operational again."