The political crisis in South Africa has deepened, after the speaker of the country's National Assembly confirmed that parliament will debate a motion to impeach President Jacob Zuma on 5 April.

On 31 March, the Constitutional Court – one of the country's highest judicial bodies – ruledZuma had "failed to uphold, defend and respect the constitution", prompting his African National Congress (ANC) party's main opposition, the Democratic Alliance (DA), to propose the motion.

Zuma,73, has been under investigation for a while, after he spent more than £11m ($15.7m) of taxpayers' money on renovations at his private residence, including building a swimming pool and an amphitheatre. Claiming at first that the upgrades to the property in Nkandla were for added security, he has since ignored official instructions to repay some of the cash, prompting calls for him to resign.

"The national assembly will on 5 April consider a motion by the DA for the removal of the president in terms of section 89 of the constitution," speaker Baleka Mbete told journalists.

The scandal-hit leader of the ANC has long been dogged by allegations of corruption since taking office in 2009.

In a recent televised address to the nation, Zuma apologised but refused to stand down, adding: "I wish to emphasise that I never knowingly or deliberately set out to violate the constitution. Any action that has been found not to be in keeping with the constitution happened because of a different approach and different legal advice."

"The matter has caused a lot of frustration and confusion for which I apologise on my behalf and on the behalf of government... Let us use the judgement to build and further strengthen our democracy," he said.

His critics, however, have not bought Zuma's contrition. DA leader Mmusi Maimane claimed to reporters that Zuma was "misleading South Africa".

"He said repeatedly he always wanted to pay. He never wanted to pay," he insisted.