Opposition parties on Friday withdrew from the parliamentary committee on Nkandla with the argument that they would not legitimise a process designed to shield President Jacob Zuma from liability for abuse of state funds.

"The opposition will not legitimise this blatant undermining of the Constitution for the protection of one man," the parties said.

The African National Congress' (ANC's) 6–5 majority on the committee means however that it still has a quorum and on Tuesday next week will continue its work in the absence of opposition MPs.

They walked out after the ruling party refused to agree to call Zuma to answer questions and to enforce Public Protector Thuli Madonsela's directive that he repay a portion of funds spent on the R246-million refurbishment of his home at Nkandla.

The ruling party maintained that there was no need to call witnesses and that the president would not have been aware of wrongdoing by officials, and that it had the right to recommend different corrective action.

Economic Freedom Fighters leader Julius Malema raised the threat that the opposition would withdraw on Thursday night after nine hours of heated debate failed to budge the ANC on these issues.

When the committee convened on Friday morning, senior ANC MP Mathole Motshekga sought to avert this by stalling a vote and invoking the ruling party tradition of seeking consensus.

But he then exasperated the opposition by arguing that though the Constitution offered a high degree of protection to Madonsela's office, it did not apply to the reports she produced.

Freedom Front Plus MP Corne Mulder termed it "a direct attack on the person of the public protector". EFF MP Godrich Gardee added that it meant the ANC was poised to revise Madonsela's finding and countered: "We are not the relevant authority, it can only be done by a court of law."

Motshekga also reiterated his view that Zuma had been right to assert last month that he was not bound by remedial action advanced by Madonsela, and rejected a united opposition plea to seek independent legal counsel to settle the argument.

Motshekga said lawyers always disagreed and the committee counted many members with legal backgrounds, including his own doctorate.

Gardee protested: "There is no sane legal mind that will come and give the interpretation given by the president of the powers of the public protector, which is what you are doing as foot soldiers."

After two and half hours in this vein, Democratic Alliance (DA) parliamentary leader Mmusi Maimane concluded: "We have reached an impasse... What is clear to me, what is very apparent, is that the ANC is not going to agree to anything. They just want us to run a ritual.

"We cannot proceed on this level," he said before leading the DA, EFF, FF Plus, Inkatha Freedom Party and African Christian Democratic Party out of the meeting.

The ANC called a media briefing at which ANC deputy chief whip Doris Dlakuda accused the opposition of acting in bad faith.

"It was clear from the outset that the opposition's desire was never to participate in the committee process in good faith, with a view to assist Parliament to arrive at sound resolutions on the matter."

But at their joint media briefing, opposition parties described the moment as a watershed and said they were deeply concerned that the ANC was subverting the role of Parliament.

Malema pointed to ANC secretary general Gwede Mantashe's comments to the media earlier this week that Parliament must protect Zuma and Deputy President Cyril Ramaphosa from insult and attack.

He said the walkout was "a serious political step" and raised the spectre of the opposition leaving Parliament entirely if the ANC did not allow the legislature to play its democratic role.

"You run a risk of people withdrawing completely from Parliament because there is no meaningful role they would play in Parliament... and once people withdraw from Parliament the spirit of our Constitution of multi-party democracy will be undermined.

"I don't think the ANC will pride itself for taking part in a Parliament that has no opposition presence. Actually they might be forced to collapse and go to elections but there is no motion about it on the table now."

The DA said the parties would now focus on settling the debate around the powers of the public protector, and if necessary it would go to court to hold Zuma to account for the Nkandla controversy.

DA federal executive chairperson James Selfe said the upcoming Western Cape High Court ruling on the case of contested SABC chief operations officer Hlaudi Motsoeneng would prove pivotal.

In that case, the DA sought an urgent interdict forcing the SABC to suspend Motsoeneng, who was appointed to the post permanently despite Madonsela's finding that the public broadcaster should replace him within 90 days.

"The issues in law are absolutely identical," he said, adding that a ruling was expected shortly.

Selfe said if the DA did not win that case, it would take the matter all the way to the Constitutional Court to seek clarity on the status of the office of the public protector.