Opposition parties serving on the ad hoc committee on misspending at President Jacob Zuma's Nkandla home on Thursday failed to persuade the African National Congress (ANC) to call Public Protector Thuli Madonsela next week, followed in short order by the president himself.

The Economic Freedom Fighters (EFF) said Zuma must not only come to tell MPs "what he intends to do in terms of paying back the money" but the committee must also interrogate his recent letter to Madonsela.

In the letter dated September 11, Zuma suggested that he was not bound by her recommendations, which in the case of Nkandla directed him to reimburse the state for luxuries added to his private home at the state's expense. EFF chief whip Floyd Shivambu said Zuma's letter questioned the powers given to the public protector by the Constitution and constituted "a deliberate defiance by President Zuma of the public protector".

Quoting from a passage in the letter where Zuma implores Madonsela to allow the current parliamentary process to take its course, Shivambu said it was clear that "we are being utilised to prevent the implementation of the public protector's recommendations".

ANC MP Mathole Motshekga countered that it was premature to decide who the committee must summon as he had not yet read the Special Investigating Unit's report on Nkandla released last week, a comment rapidly ridiculed by the EFF.

Democratic Alliance parliamentary leader Mmusi Maimane said committee members had a duty to read that report as well as Madonsela's but there was no reason not to call her next week to answer further questions on her findings.

He disagreed with the EFF that Zuma's letter was crucial to the committee's deliberations, saying it merely reflected his views, and it should not lose sight of its mandate to ensure that the remedial action recommended by Madonsela is implemented.

"The president has a view, everybody else can have a view. We must try not to get into a self-image problem here. Our job is to make sure that the recommendations are implemented."

The parties' conflicting interpretations of the committee's mandate is set to be a sticking point in coming weeks, as the ANC holds that it is to "consider" the findings of the various investigations into the Nkandla project, as well as Zuma's own submission to Parliament.

Cope leader Mosiuoa Lekota announced from the outset that his party was refusing to sit on the committee because it believed it was tasked to review the findings of the public protector, and this was unconstitutional as only a court could do so.

He was, in vain, assured by committee chairperson Cedric Frolick that the mandate given by the National Assembly was no wider than to consider the various reports on Nkandla.

The committee will meet again next Thursday and faces a race to meet its deadline of October 24 to report to the National Assembly as the next month will include a two-week recess.

However, Frolick reminded members that ad hoc committees may request extensions.