Her office has been under scrutiny after a committee overseeing her functions received a formal complaint from DA MP John Steenhuisen, casting doubt on her future.
Parliament’s portfolio committee on justice and correctional services also received a scathing response to intentions to remove her.
Mkhwebane slammed the DA and demanded a public apology in a 25-page written response to the committee.
However, MPs across the political spectrum say the outcome of a North Gauteng High Court judgment, which set aside her report, has cast further uncertainty on her position.
In her report, Mkhwebane demanded that Absa pay R1.25billion for Bankorp’s apartheid-era loan from the Reserve Bank.
“We are on record as the DA has to say that she does not have a proper understanding of her powers and the ability to perform all those functions,” said DA MP Werner Horn.
“She is not fit to hold office. If Parliament decides that a formal inquiry be instituted, it is a formal process and it is no longer a political view. But, politically, we are of the view that an inquiry must be instituted,” said Horn.
IFP MP Mfakazeleni Buthelezi said: “As the IFP we supported her appointment, but after the judgment we feel that there is no problem with instituting an inquiry.
“The judgment on its own does not mean that she is guilty of anything. It is matter of inquiring whether she is fit or not. She does not have to panic,” said Buthelezi.
Cope leader Mosiuoa Lekota warned that Mkhwebane should desist from judging her own matter and allow the committee’s process to conclude.
“She cannot be a judge of her own case, first of all. She must provide evidence to show that what they have said is not substantiated.
"She is missing the point already by passing judgment on a matter in which she must defend herself. Unless she can provide evidence, she will have to take the consequences,” said Lekota.
However, political analyst Ralph Mathekga said reviewed reports of the public protector’s office should not be seen as a sign of incompetence.
“There are some procedural issues that are being misinterpreted in all this.
"If the public protector’s report is reviewed successfully, does that mean she has to be fired?
"A review simply means that the findings could have been erroneous or the remedial action is not justifiable.
“They cannot just remove her because they disagree with her. There must be grounds that have a lot to do with her inability to carry her job as public protector,” said Mathekga.