"The gold sector has seen an increase in fatalities this year, with Sibanye-Stillwater as one of the main contributors", Mineral Resources Minister Gwede Mantashe said in a statement.
He said the two miners still trapped are "probably dead as well".
The Department of Mineral Resources and unions had been informed of the event Thursday and had representatives on the site assisting with the rescue efforts.
"Our safety systems generally work, and we'll have to do the investigations once we get our workers out".
He said the rescue operation would go on through the night.
The Association of Mineworkers and Construction Union (Amcu) said the first seismic event, measuring 2.5, occurred at about 12.23pm, followed by another measuring 2.2 at 13.17pm.
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This act holds liable an organisation with a work force of 20 or more workers to guarantee a bonus to each of its employees. On 1 May 1886, there was a general strike for the eight-hour workday by labours .
Sibanye's James Wellsted says this is the third tremor in the same area since Thursday.
Mine rescue teams were immediately mobilised.
In January a power outage trapped hundreds miners underground at the Beatrix operations in the Free State province, although all were safely returned to surface.
"Four of the ten have since succumbed to their injuries, while another six employees are still in hospital".
In March this year, 79 mineworkers were trapped underground at the Kloof Thuthukani Shaft in Westonaria after a material auto fell into the shaft.
Two more quakes were felt Friday near the Masakhane mine, part of the company's Driefontein operations, where three of the workers remained trapped and two unaccounted for. This includes this week's five deaths.