"If the [withdrawal] of charges against Zuma were made in a transparent way that would give us confidence that the rule of law has been respected," Dandala told the Cape Town Press Club.

"Some of us are concerned. We must be assured that there was no interference... no compromises made. If we get that, we will be affirmed in our belief in the independence of the judiciary."

Press reports this week said the NPA is on the point of withdrawing all charges against Zuma a month ahead of national elections expected to see him become president.

The NPA has vehemently denied the reports, which followed on the heels of fresh representations by Zuma's legal team to the prosecuting body.

These are not in the public domain and the NPA would not be obliged to disclose its reasons for withdrawing fraud and corruption charges linked to the arms deal against Zuma.

NPA spokesperson Tlali Tlali told newspapers that the prosecuting authority "would still have to consider" whether to make public reasons for any decision to drop the charges.

Opposition parties, including the Congress of the People, have reacted with outrage to the prospect of letting Zuma off the hook, saying it would point to manipulation of the judiciary and tarnish South Africa's reputation abroad.

Dandala also reiterated in his first campaign speech in the Western Cape that Cope would not enter into a post-election alliance with the African National Congress.

It would consider working with the Democratic Alliance and the United Democratic Movement, he said.