Preparations were underway on Sunday ahead of an attempt to rescue over 200 illegal miners trapped in an abandoned mine in Benoni, on the East Rand, paramedics said.

Ekurhuleni rescue services were busy stabilising the surrounding ground, ER24 spokesman Werner Vermaak said.

He said rescue cranes and a bus used as a mobile clinic had arrived on the scene.

A large boulder was covering the opening to an old shaft at the abandoned mine outside central Benoni. However the site was still too unstable to begin trying to shift it.

Earlier, Vermaak said rescue teams were able to speak to about 30 of the miners trapped near the top of the old mine shaft.

"Approximately 30 people are trapped towards the top of the old shaft and the rest down a steep tunnel."

Those near the top had told the rescue services that about 200 people were in the tunnel. The miners were found on Sunday while emergency services were conducting operations around illegal mining in the area. They heard screaming from the abandoned mine.

Vermaak said it appeared that nobody in the smaller group was seriously hurt. However, it was not known what condition the miners trapped in the tunnel were in.