Membership of any union or party should not be a death sentence in a democratic country, the Congress of South African Trade Unions (Cosatu) said on Friday ahead of its rally in Marikana.

"The ongoing killings and violent attacks on [National Union of Mineworkers] Num members and leaders must stop and cannot be allowed to continue. The law enforcement agencies need to start doing their work of apprehending the perpetrators," spokesperson Sizwe Pamla said in a statement.

He said Cosatu condemned the ongoing violence and intimidation of workers in Marikana near Rustenburg in North West.

"We strongly support the principle of freedom of association, especially for the working class. Membership of any union or any party should not be a death sentence in a democratic country."

Num member Kaizer Madiba was gunned down on November 1, while going to work.

Cosatu and Num are expected to hold a rally at the Wonderkop Stadium on Sunday.

"This rally is about reminding workers that the ongoing violence, whose main victims remain the exploited masses, is not only weakening them but, it has also shifted the focus and blame from the mine bosses who have systematically undermined collective bargaining and promoted division amongst workers," Pamla said.

"While workers are killing each other and surviving on their unemployment stipends, the mine bosses sitting in comfort enjoying profits from the very workers whose families have now been robbed of their only breadwinners."

On August 16, 2012, 34 striking Lonmin mine workers died when the police shot at them. The workers were on a wildcat strike at the time. They were demanding to be paid a monthly salary R12 500. As many as 10 people - including two policemen and two Lonmin security guards - were killed in the days before the police shot at the strikers near the Marikana koppie.

Pamla said political opportunism, populism and the culture of warlordism has undermined the efforts to find lasting solutions to the problems that led to the 2012 tragedy in the first place.

"The legacy of the Marikana tragedy should have been about changing the conditions of the mineworkers and holding the mining companies accountable for the damage that they have inflicted on the workers and communities for centuries. Unfortunately, we will not be able to achieve any of this because some have decided to hijack Marikana for narrow political and selfish ends," he said.

"Seven years later, workers are still forced to deal with the spectre of violence that continues to haunt the mining sector and the platinum belt, in particular. Marikana cannot be allowed to become a slaughterhouse for the workers and a playground for assassins."