The Democratic Alliance and Agang SA are expected to hold separate press conference in Johannesburg on Monday, with their proposed political union lasting less than a week.

On Tuesday, Democratic Alliance leader Helen Zille announced that Agang SA leader Mamphela Ramphele would be her party's presidential candidate in the upcoming general elections.

However, confusion arose on Friday over Ramphele's joining the DA.

According to a joint statement issued by Ramphele and Zille on Friday, the Agang SA founder would be welcomed into the DA at a press conference in Johannesburg on Monday.

However, following the joint statement being issued, a message from Ramphele was uploaded onto Agang SA's website.

"You may have by now seen 'joint' statements issued by the Democratic Alliance in which it is claimed that I will be accepting DA membership on Monday," she said.

"This is not true. Nor did I agree to any such statement."

On Sunday, Zille said Ramphele had reneged on the agreement to be the Democratic Alliance's presidential candidate at a meeting on Sunday despite the party negotiating in good faith.