South African police were in a standoff on Thursday with hundreds of illegal miners believed to be underground in a disused shaft, a day after a cabinet minister said the government was trying to "smoke them out".

Police have been trying for weeks to empty the abandoned gold mine in the North West province as part of a crackdown on illegal mining, which has plagued South Africa for decades through small-time pilfering and organised criminal networks.

More than 1 000 illegal miners resurfaced after police cut off their food and water supplies, but a police spokesperson said hundreds more could still be underground.

A decomposed body was brought up on Thursday, with pathologists on the scene, spokesperson Athlenda Mathe said.

On Wednesday, asked whether the government would send help to the zama-zamas - a local term for illegal miners from the Zulu expression for "taking a chance" - Minister in the Presidency Khumbudzo Ntshavheni said: "We are not sending help to criminals. We are going to smoke them out."

Senior police and defence officials are expected to visit the area on Friday to "reinforce the government's commitment to bringing this operation to a safe and lawful conclusion", according to a media advisory from the police.

Illegal gold mining costs South Africa's government and industry hundreds of millions of dollars annually in lost sales, taxes and royalties, according to an estimate by a mining industry body.