Mbalula's office on Monday confirmed that a case had been opened, after an alleged assault took place against a woman at 04:00 on Sunday morning at a Cubana in Fourways, Johannesburg."Minister Mbalula takes these allegations very serious [sic]," ministry spokesperson Vuyo Mhaga said in a statement of the "disturbing allegations".
Mbalula expected the victim to be treated with respect and dignity, and that police would proactively give feedback to the victim, he said.
"Women deserve love and protection from all of us. The police must be given space to investigate this case without fear or favour, no one is above the law irrespective of their position in society," Mbalula said.
A social media post shows images of the injuries Mandisa Duma suffered after the assault.
Another post by SABC reporter Lumko Jimlongo said the incident occurred when the woman allegedly called Manana "gay", while another said the incident occurred during a debate in Cubana over African National Congress leadership.
The ANC said in a statement that it had noted the accusations against Manana with disappointment, saying such behaviour was unacceptable.
The Democratic Alliance, meanwhile, said it was shocked and angry to learn about the alleged assault.
"We condemn this act in the strongest terms. In our country which is plagued by unacceptably high levels of gender-based violence, this behaviour only seeks to normalise and perpetuate violence against women," DA MP Hlomela Bucwa said on Monday.
"While we welcome that a criminal case has been opened against him, this is simply not enough."
She said Manana must immediately apologise and resign from his post, saying he was "unsuited to hold it".
The South African Federation of Trade Unions (SAFTU) has also expressed "disgust" over the alleged violent assault.
"It is appalling that less than a week into the month when South Africans are focussing on the problems facing women and in particular the violent attacks which they suffer on a daily basis, such a brutal crime should have been committed at all," SAFTU said in its statement.
"But far worse that it should have been perpetrated by a government minister, an elected representative of the people."
The federation further insisted on Manana's immediate suspension.
"Government ministers should be held to the highest possible standards of conduct, and if its leaders fall to come down heavily on a minister, especially one responsible for higher education, who commits such a heinous crime, the government will have forfeited any credibility and it talk of women's rights will be exposed as empty rhetoric."