The Australian Taxation Office (ATO) has suffered another setback to its systems restoration, announcing on Friday afternoon that it is not expecting service availability to its key applications before the weekend.
"Due to an unforeseen complexity in the system restoration process, our services are unlikely to be available before close of business today," the ATO said.
"We fully acknowledge the significant impact this is having on our key stakeholders, who rely heavily on the availability of our systems and services. We apologise for the inconvenience and disruption this has caused."
On Friday morning, the tax office said both ATO and Hewlett Packard Enterprise (HPE) technicians had worked through the night to restore its systems and online services; however, its Tax Agent, Business and BAS Portals, ATO online, the Australian Business Register, Standard Business Reporting, and superannuation online services were still not operational by Friday afternoon.
"While there has been significant progress on their restoration plan, the process is highly complex," the ATO said Friday. "While everything is being done to restore our systems as quickly as possible, we cannot make services available to the community until the integrity of the system is confirmed."
HPE upgraded the ATO's hardware back in 2015, and it is "basically the same" hardware used by other large clients of the IT giant.
The ATO's website, tax agent, and business portals initially crashed on December 12 and the outage continued through to December 13, when the ATO first called in HPE to help it determine the underlying cause of the problem that the ATO said was encountered for the first time anywhere in the world.
Three days later, Commissioner of Taxation Chris Jordan announced an independent review into the "unprecedented failure" and called it the ATO's worst unplanned system outage in recent memory.
At the same time, the ATO claimed almost everything was back up and running, but did admit that "some" data corruption was experienced as a result of the incident, and noted it was in the process of having the data fully restored from a back-up.
On December 20 -- more than a week after the initial hardware failure -- the ATO said it was still experiencing reduced functionality across some of its systems.
"What compounded the problem beyond the initial failure was the subsequent failure of our back-up arrangements to work as planned," Jordan explained previously. "The failure of our back-up arrangements meant that restoration and resumption of data and services has been very complex and time-consuming."
On Thursday, the tax office's systems fell over again, with the outage affecting all of its online services, including the ato.gov.au website.
Last week, the ATO appointed PwC to conduct an independent review into the long-running incident. The tax office expected the consultancy firm's review to provide insight into what actually happened and why, and what needs to be done to ensure the same incident does not occur in the future.
At the time, the ATO said it chose PwC to conduct the independent review due to the firm's "specific expertise" with the storage hardware at the centre of the incident.