Johannesburg's high net worth population is more than double that of Cairo, according to new research.

Johannesburg is the top African city for high net worth individuals, with 23,400 millionaires, according to a new report by AfrAsia Bank and New World Wealth.

The South African city was comfortably ahead of Cairo, which came in second place with 10,200 millionaires, according to the rankings. This was followed by Lagos, home to 9,100 millionaires, and Cape Town, with 8,900.

“African cities are emerging as epicentres of growth and opportunity; places where growing numbers of consumers with disposable income are congregating,” said AfrAsia Bank's chief representative officer, Colin Grieve.

“Successful entrepreneurs are seizing the opportunity to provide products and services to these expanding markets and in doing so generating wealth for themselves and their communities.”

The report highlighted that these rankings only include cities with 2,000 or more millionaires, so fast growing African cities such as Maputo, Lusaka, Abidjan, Dar Es Salaam and Addis Ababa are not accounted for.