Seventeen current members of the Administrative Appeals Tribunal (AAT) have had more than one bullying, harassment or discrimination complaint made against them since 2016.
Allegations have been made against 19 members in total, with two members no longer working with the AAT.
They include senior officials and a deputy president, with the head of the tribunal unaware until Monday that they were still serving despite the multiple complaints.
Labor senator Nita Green has been seeking information about bullying and harassment claims for many months and acknowledges that not all the allegations have been substantiated.
But she said the multiple complaints raised serious concerns about culture and accountability.
"I would suggest it is a pretty serious step for an employee to make a complaint against the AAT tribunal member, as they are people with incredible power and standing," Senator Green said.
"I would put a lot of weight to the employees making these complaints without going through an investigation process."
AAT chief operating officer Jamie Crew told Senate estimates that two members with multiple complaints made against them were no longer with the AAT, while 17 were still employed.
Three members have had three or more complaints made against them.
"The one with five or more is still a current member," Mr Crew said.
"They are still serving their initial period of appointment."
AAT registrar Michael Hawkins told senators there was an established process for dealing with complaints but enforcement options were limited.
"The options available to the president in any circumstance is to seek either an apology or an acknowledgement from the member involved, there may be counselling or the president may consider changing the members work area or practice," he said.
"Unfortunately, our code of conduct is not supported by legislation and consequently there is very little the president can formally do."
Senator Green asked AAT officials whether the fact members had multiple allegations made against them had been raised with the former Coalition government. The public servants did not know.
"I find it very troubling that there are members where there are multiple complaints," Senator Green said.
Federal Labor has long accused the Coalition of stacking the AAT with politically motivated appointees during its nine years in government.
Plum jobs worth up to $500,000 a year were extended to Liberal Party-linked individuals by the Morrison government in the dying days of the 46th parliament.
Federal Labor has also raised concerns about the legal qualifications of AAT appointees, arguing the tribunal has been politicised.
