South African authorities have issued an arrest warrant for Grace Mugabe, wife of deposed Zimbabwean leader Robert Mugabe, over the alleged assault of a South African model in August 2017.

The arrest warrant was issued last Thursday, South African Police Services spokesperson Brigadier Vishnu Naidoo told CNN on Wednesday.

"I can confirm that a warrant for the arrest of Grace Mugabe was issued last Thursday," Naidoo said, adding that police were seeking Interpol's help to enforce it.

South African model Gabriella Engels accused Grace Mugabe of attacking her in August 2017.

Engels said on Twitter that the former Zimbabwe first lady "split my head open in 3 places. With an extension cord and plug to hit me."

There was no immediate comment from the Zimbabwean government and, even with an Interpol Red Notice, it is unclear whether Zimbabwe will comply.

Grace Mugabe was granted diplomatic immunity over the incident by South Africa's former Minister of International Relations and Cooperation Maite Nkoana-Mashabane, allowing her to leave the country.

However in July 2018 a South African High Court overturned the decision, paving the way for prosecution and possible extradition.

The latest developments are another blow to Grace Mugabe, who was reportedly being lined up to replace her husband Robert as Zimbabwean leader before he was forced to resign in November 2017.

The former revolutionary leader ruled Zimbabwe for 37 years before leaving office after an apparent coup staged by the country's military.

At the time an army spokesman denied a military takeover was underway but the situation bore all the hallmarks of a coup: The military was in control of state TV in Harare, a significant army presence was at the city's international airport, and Mugabe was not seen in public.

President Emmerson Mnangagwa now rules Zimbabwe following disputed elections on July 30. (CNN)