Public Protector Busisiwe Mkhwebane "acted incompetently" and "failed" in her duties to investigate and report on the Vrede dairy project in the Free State, the Palace of Justice, which houses the North Gauteng High Court in Pretoria, heard on Tuesday.
The Democratic Alliance and Council for the Advancement of the South African Constitution (Casac) have applied to have Mkhwebane's report on the project declared unconstitutional, reviewed and set aside.
One hundred black emerging farmers were promised five cows each as part of the empowerment scheme, but never received them.
Gifted to Estina in 2013 under a free 99-year lease by the provincial agriculture department, the farm has been one of the most scandalous transactions between the Guptas and a government entity. The #GuptaLeaks revealed last year how at least R30m paid to the Guptas via the farm ended up funding the family's lavish Sun City wedding in 2013.
In the application, the DA's advocate Janice Bleazard, argued that Mkhwebane failed to investigate a complaint lodged by the party's Roy Jankielsohn.
Between 2013 and 2016, Jankielsohn submitted three complaints to the Public Protector in respect of the project, calling on the role of the provincial government and then Free State premier Ace Magashule to be probed.
However, when Mkhwebane assumed office in October 2016 she inherited a provisional report prepared by her predecessor, Thuli Madonsela.
Earlier this year, Mkhwebane quietly released the report highlighting procurement irregularities, "gross negligence" and maladministration related to the controversial project.
This was arguably Mkhwebane's most politically sensitive report.
She recommended as remedial action that Magashule "initiate and institute disciplinary action against all implicated officials involved in the Vrede dairy project".
However, the DA's view is that Mkhwebane was not "prudent" in her investigation and that senior politicians implicated in the project were not interviewed.
The DA argued that when she assumed office, Mkhwebane was required to conduct a preliminary investigation into the merits of Jankielsohn's complaint or refer the matter to another appropriate investigative authority.
"She did not do so. Instead, she purported to ignore the third complaint as a mere inconvenience.
"When the Public Protector receives complaints of impropriety or abuse of public office, she is obliged to use the powers vested in her - including her power to call for assistance from organs of state, or to refer matters to other appropriate authorities - to ensure."
Bleazard said the power vested in Mkhwebane to investigate alleged or suspected improper or prejudicial conduct in state affairs must be coupled with a duty to exercise it.
She also added that when the Public Protector received a complaint, she should implement a preliminary investigation to determine its merits.
"It is not open to the Public Protector simply to decline to exercise her investigative powers on receipt of a complaint in respect of such conduct," the party argued.
"There is no real dispute that the Public Protector failed to conduct any investigation into the matters raised in Dr Jankielsohn's third complaint."
She argued that, since Mkhwebane did not "advance" the investigation upon assuming office, there appeared to be no factual basis for the revisions made to the findings in the provisional report.
Meanwhile Casac argued that the report did not include findings relating to the "high-level politicians that played a central role in the project".
"We will submit she has failed in every aspect," advocate Michelle le Roux argued on Casac's behalf.
Le Roux said a rational Public Protector would not undo what her predecessor did, adding that it appeared that Mkhwebane diluted Madonsela's report when it came to the remedial action.
"She did not act rationally. She acted incompetently," Le Roux said, adding that Mkhwebane failed to ask Magashule questions about what happened to the project and where the money went.
The case continues on Wednesday.