The government science organisation has conceded its high-profile investigation never even had the power to make findings of workplace misconduct against CSIRO managers.

After 110 submissions alleging 130 separate episodes of bullying, just one mid-level manager is now facing disciplinary action, with action pending against another.

The organisation says that the investigation, which submitted its final report in April, formed the basis for sweeping internal reform, including the formation of an in-house investigations unit.

But complainants, who have formed a well-organised pressure group, say the latest revelations prove the CSIRO engaged in a ''$4.5 million cover-up''.

The review by former commonwealth ombudsman Dennis Pearce was launched in February last year after an ''improvement notice'' was issued by Commonwealth workplace insurer Comcare for the CSIRO installation at Canberra's Black Mountain.

Pressure for action by CSIRO management had been building for several years through the online Victims of CSIRO group, which lobbied the media and politicians for an investigations into the organisation.

But Professor Pearce’s investigation found ''no major problem of workplace bullying or other unreasonable behaviour'', rejected claims of a ''toxic culture'' and decided two accusations against outgoing chief executive Megan Clark could not be substantiated.

In answers to a series of questions from South Australian Greens Senator Penny Wright, the CSIRO has revealed it has paid law firm HWL Ebsworth $4,454,498.09 to run the investigation.

The organisation also revealed that Professor Pearce had no power to return findings of misconduct against CSIRO managers, because the administrative law expert did not actually work at the science organisation.

''Under the provisions of CSIRO’s Enterprise Agreement and CSIRO’s Misconduct Procedure, any formal finding of misconduct must be made by a CSIRO Senior Manager,'' said the answer to Senator Wright’s question on notice.

''The resulting information and recommendations from the work undertaken by Professor Pearce has been used to inform misconduct processes where appropriate.''

Andrew Hooley, a founding member of Victims of CSIRO, said his group had been unhappy with Professor Pearce’s inquiry from the start.

''The truth is, had the CSIRO actually established a credible investigation, a lot more than 130 complaints would have been received,'' Mr Hooley said.

''People chose very early on in the process to avoid the investigation, seeing it for what it really was: a $4.5 million cover-up.''

The former researcher says that members of his group are still pursuing their cases against CSIRO though other means.

''It is a real shame because so many people for so long have been calling for a truly independent investigation of their complaints but from the outset, the CSIRO was completely incapable of keeping its paws off and let the investigation run its course without attempting to control the outcome,'' Mr Hooley said.

''This investigation was never empowered to investigate the full extent of complaints against the CSIRO.''