The wife of Gabon's ousted president Ali Bongo Ondimba has been charged with "money laundering" and other offences, the public prosecutor said Friday, a month after a coup toppled her husband.

Sylvia Bongo Ondimba Valentin was charged by an investigating judge on Thursday, Andre Patrick Roponat announced on state TV channels on Friday.

She has been under house arrest in the capital Libreville since the coup in the oil-rich nation on August 30.

Her house arrest order has also been upheld, Roponat said.

One of her laywers said earlier this month that she was being kept "incommunicado outside any legal framework".

Their son, Noureddin Bongo Valentin, has already been charged with corruption and embezzling public funds with several former cabinet members and two ex-ministers.

Bongo, 64, who had ruled the central African country since 2009, was overthrown by military leaders, moments after being proclaimed the winner in a presidential election.

The result was branded a fraud by the opposition and the military coup leaders, who have also accused his regime of widespread corruption and bad governance.

Ali Bongo took over when his father Omar died in 2009 after nearly 42 years in power.