Zimbabwe's first lady remains out of sight several days after a young model claimed Grace Mugabe whipped her with an extension cord in a South African hotel.

South African authorities are weighing a request by Zimbabwe's government for diplomatic immunity for the first lady, who has not commented since the alleged assault Sunday night.

South African police have issued a "red alert" at its borders to ensure Mugabe doesn't leave undetected. They say their investigation is complete but needs a government decision on the immunity appeal.

Zimbabwe's government and state media have not publicly addressed the assault allegations.

It is not clear whether the wife of 93-year-old President Robert Mugabe entered South Africa on a personal or diplomatic passport.

Lawyers for the 20-year-old model have threatened to go to court.