An alleged illegal miner who was hospitalised after an underground gas blast at the Gupta-owned Gloria mine in Blinkpan‚ near Middelburg‚ has been arrested.

"The person who was hospitalised and counted as the sixth person [who died]‚ was in fact discharged from hospital on Thursday and is in police custody‚" said spokesperson Brig Leonard Hlathi.

"The 26-year-old man is expected to appear before the Blinkpan periodical court facing a charge of trespassing.

"Police are waiting for his passport to verify whether is he is legally in the country‚" added Hlathi.

Five people have so far been confirmed dead after the blast on Wednesday.

"Regarding the five people who died‚ three have been identified as Lesotho nationals and one is a South African‚" said Hlathi.

The dead were allegedly with a group that went into the mineshaft on Wednesday in a bid to rescue others who had gone underground three days earlier.

One body was brought to the surface along with a badly injured man who was taken to hospital in a serious condition on Wednesday. The other four bodies were retrieved on Thursday.

It remains unclear how many people are still trapped underground at the mine‚ which has been nonoperational for several months.

Hlathi on Thursday said rescue workers were experiencing difficulty. Rescue efforts were being hampered by the fact that the mine shaft was unsafe and there was insufficient ventilation and no electricity.

An inquest docket has been opened.

The Gloria mine forms part of the Optimum Coal assets bought by the Gupta family in 2016. They were put into business rescue early in 2018.