Mwelase, 31, died at the Steve Biko Academic Hospital in Pretoria on Saturday, it said in a statement.
The light welterweight boxer slipped into a coma after being knocked out in fight against Liz Butler in Pretoria on October 10.
“Minister Fikile Mbalula has yet again learnt of the passing away of another promising sporting talent of this country.
“Mwelase lost the battle and succumbed to her untimely death on 25th October,” the ministry said.
According to boxrec.com, Mwelase had taken part in four fights, suffering three losses (including the knockout leading to the coma), and a draw.
It brought the number of sporting deaths to three since Friday. Former 800m Olympic silver medallist Mbulaeni Mulaudzi was killed in a car crash on Friday. Bafana Bafana goalkeeper and captain Senzo Meyiwa was shot dead in Vosloorus on Sunday.
– Sapa
Download our app and read this and other great stories on the move. Available for Android and iOS.