South African MPs will vote in secret on a motion of no-confidence in President Jacob Zuma on Tuesday, the parliament’s speaker has announced.

Baleka Mbete made the ruling after opposition parties took the case to the Constitutional Court.

They believed that in a secret ballot, MPs from the governing African National Congress (ANC) would be more likely to vote against the president.

Zuma has survived several previous votes of no-confidence.

The ANC has governed South Africa since the end of white-minority rule in 1994, and has a huge majority in parliament.

Mbete’s decision took many by surprise and injected a new element of uncertainty into the proceedings against the presiden.

The question now is whether enough ANC MPs are prepared to make a stand against Zuma.

At least 50 out of the ANC’s 249 MPs would need to vote against the president for the no-confidence motion to pass.

ANC MP Makhosi Khoza received death threats last month after she said she would vote against the president, and branded him "a disgrace”.

Agencies