Tax office computer problems continue

The tax office is still having problems with its online systems following a major failure late last year.

A business reporting system known as SBR1 failed last Friday but was resolved that afternoon, AAP has been told.

The ATO took its systems offline to conduct a "critical system maintenance" last weekend as the agency sought to restore systems to full functionality.

It also undertook a significant amount of work over the Christmas break to ensure its website and portals are functioning properly.

Commissioner of Taxation Chris Jordan described last year's event as the "worst unplanned system outage in recent memory".

It was caused by an unprecedented failure of storage hardware, which had been upgraded in November 2015 by Hewlett Packard Enterprise.

What compounded the problem beyond the initial failure was the subsequent failure of the ATO's back-up arrangements to work as planned.

However, there was no loss or compromise of data and refunds had been fast-tracked.

The ATO has ordered an independent review to find out what happened, how and why, and what measures need to be taken to avoid such a situation in the future.