Whistle-blowers will be able to report corrupt activities via a hotline if African National Congress (ANC) head Jacob Zuma takes over as President of the country after the general elections.

Addressing thousands of people during an ANC rally in Ngwelezane, outside Empangeni, Zuma proposed introducing a national toll free number where people could report corruption.

The number would also be used to report lazy government officials.

"This is my idea that I want to put forward. The number will not only have to report corruption, but will also ensure that there is constant communication between the presidency and people on the ground," he said.

Zuma said he had noticed that very few people were reporting corruption.

A performance monitoring structure would ensure that dead wood was removed from government.

"The structure will ensure that lazy people are removed from government and replaced with competent ones."

Zuma said there were government officials who thought they were bigger than the people.

"The structure will also make sure that corruption cases are dealt with speedily because at the moment we have many people who are suspended with full pay for a long time."

Earlier on Tuesday, the party said it had penetrated the strongholds of its arch rival, the Inkatha Freedom Party (IFP).

"People have made a shift from the IFP to the ANC," said ANC spokesperson Jessie Duarte ahead of Zuma's appearance at the rally in KwaZulu-Natal's Ngwelezane Township.

"They have shifted in huge numbers. Our rallies in the so-called IFP strongholds are attended by thousands of people," she said.

She was quick to point out the ANC had not grown because of Zuma's popularity.

"We hear people saying that the ANC support has grown because of Zuma's popularity. That's not true. Zuma is not a populist. People have moved to the ANC because they have seen what the ANC government has done."

However snap surveys during ANC rallies showed that some people had moved to the ANC because they like Zuma.

They said Zuma's listening skills and passion to make education available to all young people were one of the reasons they liked him.

The IFP reacted angrily to the ANC statement that it had infiltrated its strongholds in northern Zululand. The party described the ruling party's statement as "wishful thinking".

"The ANC's ship is sinking due to internal divisions across South Africa. The only province where ANC spin doctors can pretend their party's support is growing, citing ANC president Jacob Zuma's ethnicity, is KwaZulu-Natal. This is wishful thinking," said IFP national organiser Albert Mncwango.

He said the ANC exaggerated the number of people who attended its rallies.

"The IFP has long contended that the ANC is particularly adept at bussing in supporters to other parties' strongholds to create an impression of local support. The bussing in of ANC supporters from as far away as Pietermaritzburg was at the crux of the clashes between the two parties in Nongoma in early February," said Mncwango.