Lekota angered ANC MPs with his remarks during a debate on The Presidency's budget vote.

He accused Zuma of failing to uphold his constitutional obligations by not protecting the rights of Brett Murray - the creator of the controversial painting depicting the president with his genitals exposed - and City Press editor Ferrial Haffajee, who refused to remove an image of the painting from her paper's website.

Higher Education and Training Minister Blade Nzimande objected to Lekota's accusation, saying it was so serious that it could warrant the removal of the head of state.

He said such an allegation could be made only in a separate substantive motion.

Deputy Speaker of Parliament Nomaindia Mfeketo ordered Lekota to withdraw his remarks, ruling that they were out of order.

She agreed with Nzimande's assertion that the accusation c ould be made only in a separate substantive motion.

"One of the grounds for removal of the president in terms of section 89 of the constitution is a serious violation of the constitution or of the law.

"Therefore, to accuse the president of violation of the oath of office is a serious charge indeed, which, if proved correct, could have serious consequences."

Lekota refused to withdraw his remarks, saying he disagreed with Mfeketo's ruling.

"The point that we make as to why the president broke his oath of office remains valid in our view and I am unable, therefore, to withdraw," said Lekota.

When Lekota left the National Assembly he was followed by a large number of opposition MPs.

The IFP did not join the walk-out.

The opposition tried to challenge the ruling but its objections were not entertained.

Mfeketo earlier ordered Deputy Trade and Industry Minister Thandi Tobias-Pokolo to withdraw a derogatory remark about DA p arliamentary leader Lindiwe Mazibuko during the same heated debate two weeks ago.

Tobias-Pokolo called Mazibuko "the lady with the funny hairstyle". She apologised and withdrew her remark.