JOHANNESBURG (Reuters) - South Africa’s High Court on Monday overturned a decision by the government to grant Zimbabwe’s former first lady Grace Mugabe diplomatic immunity after she was accused of whipping a woman with an electric cord.

FILE PHOTO: Former Zimbabwean president Robert Mugabe, accompanied by his wife Grace, arrives to vote in the general elections in Harare, Zimbabwe, July 30, 2018. REUTERS/Mike Hutchings

Model Gabriella Engels, the woman behind the assault allegation, last August 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 South Africa where the opposition Democratic Alliance also challenged the ruling.

Mugabe denied assaulting Engels with an electric cable, saying an “intoxicated and unhinged” Engels had attacked her with a knife. South African advocacy group 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 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.

Willie Spies, a lawyer for Afriforum, said the National Prosecuting Authority (NPA) should now take action to prosecute Grace Mugabe and seek her extradition from Zimbabwe to South Africa. Spies said if the NPA failed to take action, Afriforum would start proceedings against Grace Mugabe.

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

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.