South Africa's president is facing calls to order an inquiry into a police operation that was meant to combat illegal mining but ended up leaving 87 miners to die underground as authorities attempted to force them to surrender during a monthslong standoff.

It will be a "mammoth task" to identify the bodies brought up from a disused mineshaft in South Africa this week, a police spokesperson says.

Illegal mining is common in parts of gold-rich South Africa. Typically, undocumented miners known as zama zamas - from an isiZulu expression for "taking a chance" - move into mines abandoned by commercial miners and seek to extract whatever is left. Some are under the control of violent criminal gangs.