When African National Congress delegates choose their next president it must be somebody who can stand up to President Jacob Zuma, the Southern African Catholic Bishops' Conference (SACBC) said on Monday.
"The ANC owes it to the country to ensure that the new ANC president, to be elected at the end of the year, has both the political capacity to demand accountability from the current president and the ethical credibility required to lead from the front in the fight against corruption in our country," said Bishop Abel Gabuza, chairperson of the SACBC's Justice and Peace Commission.
In the church body's opinion, not only had corruption worsened under Zuma's watch, but the state's resolve to fight it had weakened.
Greed and corruption had become normal, to the point that public services - such as schools, licence renewals and home affairs - had become "collection points for bribes", Gabuza said.
"This sickness is worsening with time because the president and some of the Cabinet ministers have, for a significant period of time, lacked the levels of leadership integrity and credibility that are necessary to challenge greed and corruption."
The SACBC said that ANC delegates to the ruling party's policy conference at the end of June should consider a policy to establish an anti-corruption court.
And, following the #GuptaLeaks allegations that are being reported in the media, the church body recommended that those implicated in the emails should resign, if the allegations against them were true.
"The leaked emails, if they are authentic, show that the president's patronage network, as well as its plans to plunder state resources, is more complex and expansive than we thought," said Gabuza.
He called for a policy demanding compulsory disclosure of corporate donations to political parties and politicians, and for the Johannesburg Stock Exchange to make it compulsory for public companies to report which political parties or politicians they fund.