Johannesburg mayor Herman Mashaba was due on Monday to launch the start of a R144-million expansion project for the country's biggest fresh produce market.

The Mandela Market, an informal satellite market on the City Deep property, currently totals around R250-million in annual purchasing and this is expected to rise after the expansion.

"The Mandela Market currently provides 71 informal traders with the opportunity to generate their own income, often allowing them to educate their children or to buy a house," the city council said in a statement.

"After the upgrades are complete, an additional 28 stalls will be created."