12 ATO workers lose job for privacy breach

Thirty tax office workers have been investigated and 12 have been sacked over the unauthorised access of taxation records this financial year.

"Stupid people trying to look at their friends," Australian Taxation Office commissioner Chris Jordan told a Senate hearing in Canberra on Tuesday.

"To lose your job for having a look at someone's records that you weren't supposed to is pretty severe."

The committee was told about the investigations against the backdrop of an alleged $165 million payroll tax fraud case that has snared the children of ATO deputy commissioner Michael Cranston.

Some workers were reprimanded or fined.

There were 23 cases of unauthorised access to tax files in 2015/16.