Former president Thabo Mbeki has encouraged MPs to vote honestly on the motion of no confidence on Tuesday afternoon.
During an interview with freelance journalist Vauldi Carelse in Kenya, Mbeki said he hoped that African National Congress (ANC) MPs will discharge their responsibility to make a proper judgement.
"They are called upon to exercise oversight over the president of the republic, and the head of government and head of state. One hopes that those MPs will discharge that responsibility to make a proper assessment as to… do they have confidence in this president, depending on what the president has been doing. They have got to make that assessment."
He applauded National Assembly Speaker Baleka Mbete for deciding that the voting would be via a secret ballot, adding that this would allow MPs to vote truthfully without fear that the ANC might punish them if they vote in support of the motion of no confidence.
"So that they vote honestly according to their consciences and according to the information that they have," Mbeki said.
The ANC's secretary general, Gwede Mantashe, has said on numerous occasions that MPs who vote with opposition parties would be disciplined and stood a chance of losing their jobs.
Mbeki said the political opinion in the country was dire, adding that MPs must "recall they are representative of the people and must therefore represent the people in terms of what they do this afternoon".
"We all hope that they will do indeed that, vote honestly."
Mbeki is in Kenya overseeing the country's national elections.