The African National Congress (ANC) looks set for a massive internal debate on whether it will support the impeachment of Public Protector Busisiwe Mkhwebane or not.

While ANC secretary-general Ace Magashule told the Sunday Times "principled" ANC MPs would not vote with the opposition for any motion that would lead to the sacking of Mkhwebane, Transport Minister Fikile Mbalula defiantly tweeted on Sunday she "is a hired gun not the Public Protector".

He also challenged Magashule's assertion the ANC's position had not been revised since the national executive committee supported her appointment in 2016, and hence party MPs would be constrained by this party line against voting for a motion that would lead to her impeachment.

Mbalula openly accused Magashule of distorting the ANC's policies and viewpoints.

ANC MP Mervyn Dirks has been particularly outspoken about not supporting any motions to impeach Mkhwebane, saying this would be an attack on both her and a Chapter 9 institution.

He said a damning preliminary report done by an independent panel appointed by National Assembly Speaker Thandi Modise - which said there was overwhelming prima facie evidence of incompetence, repeated errors and misconduct - was not proper parliamentary procedure.

It is not clear if Dirks had read the report.

He is one of the ANC MPs who got rid of Makhosi Khoza from the public service committee. Khoza broke ranks to vote in favour of a motion of no confidence in former president Jacob Zuma at the time. Dirks also previously unsuccessfully tried to block a debate on state capture.

Sanusha Naidoo from the Institute for Global Dialogue said the ANC's factionalism and fragmentation had seeped into the institutions of state.

She added under Zuma, most MPs supported him and Parliament became complacent.

"It did not perform its oversight role in the way it should have been doing in the context of separation of powers."

If this was indeed different under President Cyril Ramaphosa, it raised the question as to how much traction Magashule's orders would have, Naidoo said.

Lawson Naidoo from the Council for the Advancement of the South African Constitution said the vote on whether to institute an inquiry against Mkhwebane was not a matter of political grandstanding.

"There is a comprehensive report from an independent panel established by the speaker, and it should be the responsibility of MPs whether they should properly discharge their constitutional oath of office to consider that report and make a determination from there on," he added.

"If the ANC as a political party will have to consider that collectively, it's fine, but has to be based on evidence in the report," he said. "The evidence is unequivocal."

Naidoo added should Parliament ignore the independent panel report, this could likely lead to its decision to be challenged.

The National Assembly is set to decide next Monday whether to institute an inquiry into Mkhwebane's fitness to hold office.

Removing her requires a two-thirds majority in Parliament, or 267 votes, while the motion to hold an inquiry into her fitness to hold office needs 50% plus one, or 201 MPs' votes.

The ANC has 249 National Assembly seats, while the DA has 89 and the rest are shared by a number of smaller opposition parties.