Grace Mugabe accompanies her husband, former Zimbabwean president Robert Mugabe to a polling station to cast his vote. Picture: Mike Hutchings/Reuters

Johannesburg - A lawyer for Afriforum said if the National Prosecuting Authority (NPA) failed to take action to prosecute Grace Mugabe and seek her extradition to South Africa, the advocacy group would start proceedings against the former Zimbabwean first lady.

"The ball is in their court now," Willie Spies said, adding that Afriforum had argued that Grace Mugabe committed the attack on Johannesburg model Gabriella Engels while she was on a private visit to South Africa and therefore did not qualify for diplomatic immunity.

The Johannesburg High Court on Monday overturned a decision by the government to grant Grace Mugabe diplomatic immunity after she was accused of whipping Engels with an electric cord.

Last August Engels filed a court application challenging the government's decision.

Grace Mugabe returned to Zimbabwe immediately after South Africa granted her diplomatic immunity, allowing her to evade prosecution for assault and causing a row in which the DA also challenged the ruling.

Mugabe denied assaulting Engels with an electric cable, saying an "intoxicated and unhinged" Engels had attacked her with a knife. Afriforum, which represented Engels, dismissed the allegations as lies.

Former president Robert Mugabe, 94, accompanied by his wife, cast his vote in a Harare township on Monday in Zimbabwe's first election that does not include his name on the ballot paper since the country gained independence from Britain in 1980.

According to Engels, an irate Grace Mugabe burst into the room where she was waiting with two friends in a Johannesburg luxury hotel suite to meet one of Mugabe's sons last August and started attacking her with an electric cable.

Photographs which were taken by Engels' mother soon after the incident showed gashes to the model's head and bruising on her thighs.

Judge Bashier Vally ruled that the decision to grant diplomatic immunity was inconsistent with the constitution.

NPA spokeswoman Phindi Mjnonondwana said the case was still in the hands of the police and had not yet been sent to the NPA for action. However, NPA spokesman Luvuyo Mfaku said South Africa and Zimbabwe had previously cooperated on extraditing suspects from one country to the other. 

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