The significant change in South Africa's class structure in the past 18 years has implications for the ANC, according to national executive committee member Joel Netshitenzhe.

"The fundamental implication of these social dynamics is that the changing class structure within the black community... happens because of opportunities in the political or public sphere," he wrote in the latest volume of the ANC Today.

Research showed that South Africa's middle class increased from about 10 percent of the population in 1994 to around 20 percent in 2011, Netshitenzhe said.

The largest growth in the middle class had been among blacks, where it had doubled since 1994.

This had implications for the African National Congress, which has been in power for 18 years, for what Netshitenzhe called the "sins of incumbency".

He said that while the party spoke of the values and culture of the "struggle", it was no longer living under the struggle, but in an advanced capitalist society with a small open economy under conditions of globalisation.

The emerging middle class did not have historical assets and had to support large extended families, leading it to take on debt.

"Having dipped their toes into that lifestyle, but with no such historical assets as are available to the white middle and upper strata, some then try to acquire the resources by hook or by crook."

Many blacks gained access to the middle class through leadership positions at local government level, at university student organisations and at trade unions or through the civil service.

"While there is a new crop of young black professionals and entrepreneurs who are rising on the social ladder only due to their skills and acumen and do not require affirmative action, these are still the exception that proves the rule," he said.

The position of this new middle strata was therefore tenuous, insecure and about survival, Netshitenzhe said.

"The sins of incumbency derive in large measure from this."

It led to patronage and corruption.

"In pursuit of numbers, a price is attached to a conference delegate's vote.

"And to paraphrase a lecturer at a recent Gauteng political education workshop, a toxic leadership then begets toxic members, some of whom actually demand financial and other incentives to vote in particular ways."

Netshitenzhe said the ANC had to consider whether this should be dealt with only as an internal issue, as it could negatively affect infrastructure spending; the delivery of text books; the quality of legislation passed by Parliament; and salary demands of the lower middle strata in the public service.

He said the ANC's discussion document on organisational renewal, to be debated at its policy conference in Midrand next year, offered proposals on dealing with the problems of political incumbency.

These included "a radical shift in the management of leadership contestation so we can dispense with the current pretence that everyone is waiting for October when nominations will start, while people are actually organising factional meetings about slates in the middle of the night".

He was referring to the party's national conference in Mangaung in the Free State in December, when new leaders will be elected. The leadership battle officially opens only in October.

"We may need to go even further and state clearly that members who wish to stand for particular positions should declare, get vetted, afforded a platform in the branches and regions to explain their proposed value addition; and get disqualified if they break the rules," Netshitenzhe suggested.

Netshitenzhe is the executive director of the Mapungubwe Institute of Strategic Reflection.