Eleven men who became trapped in an illegal gold mine in South Africa were rescued on Sunday, but an unknown number remained underground fearing arrest.

The men, who were all uninjured, were immediately handed over to police. Rescue officials said many others were now able to leave the mine but had refused to come out while officials were present.

"We managed to retrieve 11 young men. We believe they are South Africans, they have been treated and handed over to the police," municipal emergency and rescue services official Rogger Mamaila told AFP.

"Yes, there is a possibility that there could be more, but we don't know and we are not going to send any of our rescuers down there."

Police spokesman Mack Mngomezulu told AFP a number of men remained in the abandoned mine east of Johannesburg and were refusing to come out.

The number of people still down there remains unclear -- around 30 miners who were trapped at a shallow level had earlier told rescuers from a private operator ER24 that there were 200 others stuck at a level underneath them.

That was never confirmed, however, with local municipal officials insisting there were only around 30 people trapped.

Mamaila declared the rescue operation closed around two hours after the 11 were brought to the surface.

"Should there somebody who was not brave enough to come out, at least we removed the boulders and have created a free passageway," said Mamaila. "It's for them to decide when to come out."

Municipal officials said the workers went down on Saturday into the mine using a shaft dug illegally behind a cricket stadium in the Benoni district east of Johannesburg.

But police suspect some of them had been underground for up 12 days.

Many are thought to be former mine workers who are familiar with the geography of the mines and can walk for several kilometres underground and possibly come out through other exit points, according to police.

Illegal mining in the bowels of South Africa's abandoned pits has long plagued the world's sixth-largest gold producer, with diggers -- known as "zama zamas" (try, try) -- living sometimes for months underground to smuggle the precious metal.

- Accidents commonplace -

The men became trapped when large rocks fell and blocked the entrance to the shaft, and were able to climb out when rescuers using excavation equipment cleared the way.

Police on patrol nearby discovered that the men were trapped in the mine when a passer-by said he had heard people screaming for help.

Accidents are commonplace in South Africa's mines, which are the deepest in the world.

At least eight miners were killed nearly two weeks ago after an earth tremor sparked an underground blaze at a Harmony Gold mine west of Johannesburg.

In July 2009, nine workers were killed in a rock fall in a platinum mine.

The same year, at least 82 people digging illegally in an disused gold mine shaft died when a fire broke out underground.

Minerals Minister Susan Shabangu last week lashed out at the poor safety record at regulated mining operations, where 14 deaths have been recorded in the first seven weeks of this year.

"One death is one too many," she said on Thursday.

Throughout the 20th century, an estimated 69,000 people died in South Africa's mining industry, according to a government-sponsored commission of inquiry.

But the number of fatal accidents has fallen sharply in recent years.

According to union figures, 112 people died in the mines in 2012.