Participating in a debate on Parliament’s R2.2 billion budget, Mthembu said ANC MPs were deployees of their party and had to vote according to its standing decisions and principles.
He lashed out at opposition parties who have called on ANC MPs to vote according to their conscience.
“It is very surprising that ANC members of Parliament are expected to vote against its own decisions and resolutions and party line, while all other parties are expected to vote according to their party mandates,” said Mthembu.
“This is not only disingenuous and double standards…but it makes a mockery of the political party system.”
He accused the DA and the EFF, South Africa’s two biggest opposition parties, of extreme “hatred” of Zuma.
National Assembly Speaker Baleka Mbete warned against “judicial overreach” and said the courts should stay out of Parly’s business.
Parliament was able to resolve disagreements between its members and did not need the courts to tell it how to do its job, she argued.
In recent months, Mbete and Parliament have been cited as respondents in court actions launched by opposition parties.
This included a case where opposition parties want a secret ballot when the debate on the motion of no confidence in President Jacob Zuma takes place. The Constitutional Court has yet to rule on the matter.