Zimbabwe has blocked flights by South Africa's government-owned airline amid tensions over allegations that Zimbabwe's first lady assaulted a young model.

Update 7.09pm: Lawyers for the young model who claims Zimbabwe's first lady Grace Mugabe assaulted her in a Johannesburg hotel have said that her family has been approached with an offer of money to drop the allegation.

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.

The wife of Zimbabwe's president has been accused of assaulting a young woman at a hotel in South Africa.