South African officials are debating whether to grant diplomatic immunity to Zimbabwe's first lady Grace Mugabe, who is accused of assaulting a 20-year-old model in Johannesburg this week.

Mugabe, 52, remains in South Africa after a day of intense speculation over her whereabouts, South African police said in a Wednesday statement.

The police said the Zimbabwean government asked for diplomatic immunity for a suspect involved in the alleged assault. The police have declined to name Mugabe, a possible successor to her husband President Robert Mugabe, in the case as she has not yet appeared in court.

READ MORE: 'Under Trump, Zimbabwe might be off the radar'

Mugabe's immunity request is currently under consideration, Clayson Monyela, a spokesman for the Department of International Relations and Cooperation told The Associated Press.

Acting national police commissioner Lesetja Mothiba said earlier on Wednesday that police and national prosecutors wanted to charge Mugabe, according to the African News Agency. "Our position was that she must go to court," he said.

Gabriella Engels registered a case with police on Monday accusing Mugabe of attacking her with an extension cord in a luxury hotel in a Johannesburg suburb late on Sunday evening.

Engels said she had been in a hotel room with mutual friends of Mugabe's two sons, who live in Johannesburg, when the first lady burst into the room and allegedly assaulted her. Photos of Engels posted on social media show a bloody gash on her forehead that she claimed was a result of the encounter.

Criminal lawyer Riaan Louw said diplomatic immunity would not apply if Mugabe had indeed entered on private business.

"If she wasn't here on official business, that rules out the possibility of diplomatic immunity," Louw told Reuters news agency.

However, given the potential for diplomatic fallout, South African prosecutors could yet decide not to prosecute if they thought the injuries were not too severe, he added.

Confusion over whereabouts

Confusion over whether Mugabe was still in the country flared up on Tuesday after South Africa's police minister said she was due to appear in a South African court and she did not show up, fuelling speculation she may have returned to Zimbabwe.

Police clarified on Wednesday that while the suspect had failed to present herself to police to obtain a "warning statement" about the case, she remained in the country and had sent her lawyers and Zimbabwe government officials to tell police she intended to request diplomatic immunity.

"Discussions with the suspect's lawyers and the Zimbabwean High Commission representatives are taking place to make sure that the suspect is processed through the legal system," the police statement said.

Engels told the AP she would be willing to face Mugabe in court.

"I want to go to court because I really feel like she should go to jail for what she did to me," she said. "I don't want her to get away with this. Because what happened to me was not OK."

Mugabe has been accused of assaults during other overseas trips, including a 2009 visit to Hong Kong in which a photographer accused her of beating him up.

Zimbabwe's state broadcaster reported late on Wednesday that President Mugabe had left for South Africa to attend a regional summit.

Possible successor to husband

Grace Mugabe has been touted as a possible successor to her 93-year-old husband, who has ruled Zimbabwe since 1980.

Grace Mugabe was in the news in late July when she challenged her husband to name his preferred successor.

READ MORE: Zimbabwe's season of rising discontent

She has taken on a larger public role in recent years, speaking regularly at meetings to drum up support for her husband and heading the women's league of the ruling ZANU-PF party.

In speeches this year the president has often slurred his words, mumbled and paused for lengthy periods.

His reign has been marked by brutal repression of dissent, mass emigration, vote rigging and a sharp economic decline since land reforms in 2000.