Thousands of mine workers have gathered around a rocky hill to mark the anniversary of the deadliest protest in South Africa in decades.

Four years ago, police shot dead 34 miners at Marikana who were striking over low pay and poor living conditions.

Miners say those conditions have not improved since the shooting shocked South Africa and again exposed the tensions between mining companies and black workers who are often migrants.

Tuesday's ceremony of remembrance was peaceful. Miners sang, danced and carried sticks.

Squalid living conditions without sewer systems or other basic services are a problem for mine workers across South Africa, whose economy was built on the mining industry.

Leaders of the country's most prominent opposition parties used the commemoration to appeal for justice.