Malema is the first politician to address the miners at the site during a more than weeklong saga in which 10 people were killed before Thursday's shootings including two police officers butchered to death and two mine security guards whom strikers burned alive in their vehicle. He said he had come because the government had turned its back on the strikers.
Strikers complained earlier that President Jacob Zuma had not come to hear their side of the story when he flew to the Marikana platinum mine on Friday, cutting short his part in a regional summit in neighboring Mozambique so that he could visit wounded miners in the hospital.
Zuma said he was organizing a commission of inquiry to get to the truth about the shootings.
Malema, who was expelled in April from sowing divisions in Zuma's African National Congress party, charged some top-ranking ANC members had shares in the Lonmin PLC platinum mine and implied that they had no interest in seeing miners earn higher wages. Some 3,000 drilling operators at the mine, 70 kilometers (40 miles) northwest of Johannesburg, have been demanding an increase from the minimum wage of R5,500 ($690) a month to R12,500 ($1,560).
Malema called for Zuma and his police minister to resign or back the striking miners' wage demands a call that brought cheers from the rally.
"President Zuma presided over the massacre of our people," Malema said.
When Malema arrived, the women ululated their welcome and men who had been sitting stood up and clapped. There were more cheers when Malema persuaded police at the scene to withdraw several hundred meters with their armored cars.
South Africans are in shock over the killings. The police said they acted to save their lives after a group of miners armed mainly with machetes and clubs charged at them, and at least one miner shot at them.
Police responded with volleys of automatic gunfire and pistols.
Video replayed by TV stations reminded South Africans of apartheid-era scenes of white police officers opening fire on black protesters. This time the police were black, but the scene has South Africans debating the failure of the ANC to deliver on basic promises to provide better lives with homes, jobs, health and education.
The Lonmin miners live in corrugated iron shacks without running water or electricity. People like the strikers ask why their government, running Africa's richest nation, has not been able to improve their lot nearly 20 years after the ouster of apartheid.
The ANC's youth wing, which Malema once led, argues that nationalization of the nation's mines and farms is the only way to redress the evils of the apartheid past. Zuma's government has played down those demands.
Britain's Foreign Office on Saturday supported Zuma's call for an inquiry into the shootings.
"We are shocked by the loss of life at the Marikana mine in South Africa and send our condolences to the friends and family of all those who have died or been affected," Britain's Foreign Office said in a statement. "We further welcome President Zuma's announcement of a Commission of Inquiry, as well as National Police Commissioner General Riah Phiyega's confirmation that the South African Police Service would co-operate fully with an investigation into these tragic events."