A fire in a Port Melbourne data centre downed systems for education and research sector superannuation provider UniSuper for more than a day, leaving members unable to access their accounts.
On Wednesday UniSuper users found themselves locked out of the member portal on the provider's website.
A message recorded on UniSuper's support hotline said the problems were caused by a fire at a data centre that triggered the shutdown of key systems.
UniSuper spokesperson Catherine Dohrmann confirmed the outage to iTnews.
"Early Wednesday morning, an incident at one of our data centres triggered a partial system shutdown. A number of our systems and services were impacted," Dohrmann said.
"The direct impact on our members was limited to the outage of our telephony system and MemberOnline portal."
No data was lost or compromised in the incident, Dohrmann said.
UniSuper's team worked throughout Wednesday night to restore the provider's systems for member services, which they were able to bring back up on Thursday.
Dohrmann declined to name UniSuper's data centre provider, however images provided to iTnews indicate it was an Interactive facility.
UniSuper said it is waiting on a report from its data centre provider as to what happened during to cause systems shutdown.