The DA is set to table a motion in Parliament on Tuesday demanding a committee be set up urgently to probe the Nkandla controversy, failing which it will take the matter to court.

Democratic Alliance federal executive chairman James Selfe said President Jacob Zuma was deliberately undermining the office of the Public Protector.

This was by failing to respond in full to her findings on the R246 million upgrade of his private homestead in Nkandla, KwaZulu-Natal, for more than 130 days after she gave him two weeks to do so.

This, Selfe said, flew in the face of section 181 of the Constitution, on which the DA would base an eventual court application.

"The DA will consider launching a court application to compel the president to submit his full and comprehensive response, so as to end this unconstitutional undermining of the public protector.

"This will become necessary should our motion today to establish the Nkandla ad hoc committee not see immediate outcomes."

Section 181 of the Constitution obliges organs of state to help and protect Chapter Nine institutions, like the Public Protector, to ensure their effectiveness.

In her report, titled "Secure in Comfort" and released in March, Public Protector Thuli Madonsela found Zuma had benefited unduly from the work at Nkandla and should pay back a portion of the money spent to the state.

Selfe said Zuma's partial reply to Madonsela in April fell short of what was required of him by law.

"He certainly didn't give his comments and actions. He certainly didn't take the actions that are required of him to repay what was clearly upgrades to his own personal residence.

"He now needs to tell Parliament what he is going to do about it."

At the weekend, African National Congress Chief Whip Stone Sizani said Parliament would reconstitute an ad hoc committee on Nkandla once the president made his written submission to Parliament to indicate how he planned to handle the matter.

But DA parliamentary leader Mmusi Maimane said this commitment lacked a clear timeframe and the opposition therefore feared the president was likely to delay his response further.

"It is very open-ended and in many ways gives the president an open cheque to do in this instance as he pleases. So in the absence of a deadline for the president to submit his reply, and his current trend for feet-dragging in other matters, we hold no confidence and no weight to the statement that was issued by the ANC."

The DA said it was imperative that an ad hoc committee considered Madonsela's findings, Zuma's response and suitable punishment for any wrongdoing related to the project. It should invite Zuma to appear before it, the party said.

In June Zuma undertook to give a comprehensive response to the Speaker within 30 working days, but this month said he would only do so once the Special Investigating Unit (SIU) had completed its probe.

The SIU said its work has been delayed, in part because its investigators were only granted access to Nkandla more than six months after the president issued a proclamation authorising the probe in December.

Maimane laid the blame for this at Zuma's door.

"In this instance I think the delay has been caused by the president. I think if he was wanting to be co-operating in terms of this report he should make it easy and the institutions of government must be allowed access."