Johannesburg - Over 30 people were killed when Police opened fire after failing to disperse strikers armed with clubs and machetes at the Marikana mine.
Clashes between police and striking miners came toa head when police opened fire in an attempt disperse striking miners.
The powerful National Union of Mineworkers put the figure at 36, according to AFP news agency.
The incident came after several days of violent strikes in which 10 people were killed, including two police officers who were hacked to death.
The Marikana mine incident was one of the bloodiest police operations since the apartheid era.
The Lonmin-owned platinum mine has been at the centre of a violent pay dispute, exacerbated by tensions between two rival trade unions.
South African Police Minister Nathi Mthethwa confirmed the toll on Friday saying that a lot of people were injured and “the number keeps on going up."
Police were sent to break up the protest of some 3,000 miners who had gathered on a hillside overlooking Marikana, which lies about 100 km (62 miles) north-west of Johannesburg, to call for a pay rise of more than $1,000 (£636) a month.
The circumstances that led police to open fire remain unclear, but reports from eyewitnesses suggest the shooting took place after a group of demonstrators rushed at a line of police officers.
Police, armed with automatic rifles and pistols, first used water cannon, tear gas and stun grenades in an attempt to break up the protest but when protesters surged towards them with machetes, they fired dozens of shots, witnesses said.
Police ministry spokesman Zweli Mnisi defended the actions of police, saying they had a right to defend themselves.
In a statement, President Jacob Zuma said he was "shocked and dismayed at this senseless violence".
"We call upon the labour movement and business to work with government to arrest the situation before it deteriorates any further," he added pointing out that an investigation into the incident had been launched.
The stand-off has been exacerbated by rivalry between two trade unions, with the Association of Mineworkers and Construction Union (AMCU), a new group, seeking to challenge the dominance of the National Union of Mineworkers (NUM).
The NUM is seen as being close to the ruling African National Congress (ANC) and the two groups were allies in the fight to end white minority rule, although relations between the ANC and the unions have worsened in recent years.
South Africa is the largest platinum producer in the world and the dispute has already affected production. Lonmin, the world's third-largest platinum producer, has encountered similar labour disputes at the Marikana mine. In May 2011, the company sacked some 9,000 employees after a strike.