The incident began when miners from the opposing, unregistered union allegedly prevented hundreds of employees leaving after they had finished their night shift on Monday at the Modder East mine to the east of Johannesburg.

Some 15 miners were wounded in the ensuing scuffles, with at least one suffering a serious head injury, the mine's chief, Jon Hericourt, said.

He claims a paramedic and an officer went into the mine to bring the man to surface, but were also taken captive.

Mr Hericourt, who oversees New Kleynfontein Gold Mine company, which manages the mine, said he did not know exactly how many of the miners were being "held hostage" by those from the other union.

He said there were at least 543 employees underground in various sections of the mine, including engineers.

The National Union of Mineworkers (NUM), which is the only recognised union at the mine, said more than 500 of its members, including female workers, were being held by "hooligans."

The situation stems from a union dispute.

Mr Hericourt blamed members of the rival Association of Mineworkers and Construction Union (AMCU), saying it had demanded to be the sole syndicate representing the miners at Modder East.

AMCU contested Mr Hericourt's version of events, saying miners had conducted a sit-in protest in support of the syndicate.

The mine boss listed hammers, picks, shovels and other mining equipment in the depths that could potentially be used as weapons.

NUM called for police intervention to "arrest the hooligans holding [their] members against their will".

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Police were sent to the mine but have not been able to reach anyone underground despite the use of mine telephones and two-way radios.

The rivalry between NUM and AMCU has been longstanding, having originated upon the latter's formation in 1998.

The two have been competing for bargaining rights over various South African mines, and their feuding was partially responsible for the Marikana massacre of 2012, when 34 miners on strike were killed by police.