Zimbabwe's first lady Grace Mugabe File picture: Tsvangirayi Mukwazhi/AP

Parliament - The question on whether it was legal to grant Zimbabwean First Lady Grace Mugabe diplomatic immunity after she allegedly viciously assaulted a young model with an electrical cord should be left to the courts, Deputy President Cyril Ramaphosa said on Wednesday.

Answering questions in the National Assembly, Ramaphosa would not be drawn on what his personal thoughts were, but said the courts would rule on the matter and Parliament was also looking into the matter.

"This is a difficult case in terms of balancing diplomatic imperatives against the imperatives of natural justice," Ramaphosa said.

"In the end it is the courts of our country who will make a determination."

He added that Parliament's portfolio committee on international relations was also looking into the matter, while the court application was brought by the Democratic Alliance (DA) and civil rights group Afriforum.

Ramaphosa said International Relations Minister Maite Nkoana-Mashabane indicated she made the decision to grant Mugabe immunity in terms of the Diplomatic Immunities and Privileges Act. 

Nkoana-Mashabane was in the firing line earlier on Wednesday when DA MPs objected to her failure to appear before the portfolio committee on international relations on the Mugabe matter.

The minister sent a letter to the committee saying she could not appear because the DA's high court application made the matter sub judice.

“This is blatant misuse of the sub judice rule which does not apply in this case,” the opposition party had responded.

Nkoana-Mashabane extend diplomatic immunity to Zimbabwean President Robert Mugabe’s wife Grace after she allegedly assaulted a South African woman in August.

The decision is being challenged in court by the young model who claims Mugabe savagely beat her with an extension court, Gabriella Engels, and Afriforum.