South Africa's Sibanye Stillwater said on Friday that rescue efforts were underway for 289 mine workers trapped underground at its Kloof gold mine near Johannesburg.

"We can confirm that we had an incident at Kloof 7 shaft and are busy with making safe and shaft exam procedures, whereafter we will then hoist the employees out to surface," said a spokesperson for Sibanye.

The spokesperson said all workers were safe and accounted for and the company was in the process of providing them food.

"We expect the situation to be resolved by about midday today," the spokesperson said.

The National Union of Mineworkers (NUM) earlier said it had received reports of the incident, which it said happened at around 1000 pm (0800 pm GMT) on Thursday.