Deputy President Cyril Ramaphosa said the first step to economic transformation is the eradication of corruption.
"We transform it (the economy) firstly by ending corruption in our ranks. We must do whatever we can. When we end corruption...then companies will invest in our economy," Ramaphosa said.
"We must transform ourselves, we must transform the way we work, we must transform the economy. We must make sure that there is a rule of law in our country.We must be people who will follow the rules."
The presidential hopeful was speaking at the South African Communist Party's Red October Rally in Mpumalanga on Saturday.
The event was attended by national and provincial leaders of the SACP, Cosatu, Sanco and ANC chief whip Jackson Mthembu were also present.
Ramaphosa said one of the reasons why the economy is in "dire straits" is because the country's public enterprises have not been "working as well as they should have".
"We say it is disempowering our people and disempowering our economy...We want our economy to pump on all cylinders...it won't be able to do so unless we conserve our resources," he said.
"Those resources that have therefore been stolen must be brought back. We are unable to effectively address the economic burden of the past because our resources have been wasted...We have to restore our people's confidence in our ability to take their struggle forward."
He also spoke about land expropriation, saying those who "stole the land" must have it returned.
"We must make sure that the land is brought back to our people...Those who were removed from our land must have their land returned and those who stole that land must have that land returned back to our people," he said.
Supporters from various branches in the province as well as members of the ANC's Women's and Youth Leagues packed the Nelspruit Rugby Stadium where the event was held, filling the stands and huddling together on the grass in front of the main stage.
His presidential competitor, Nkosazana Dlamini-Zuma, also took her campaign to the province on Friday and Saturday.
Dlamini-Zuma arrived in the province on Friday to meet with local traditional leaders in the KwaMhlanga region and continued on Saturday when she delivered the keynote address at an ANCWL rally in the same area.