The Boston City Council Wednesday passed an ordinance which if enacted would force the city to divest all public funds from firms doing business in South Africa and Namibia.

Mayor Raymond L. Flynn must sign the measure before it goes to the state legislature for approval. A mayoral aide said yesterday Flyne would probably sign the measure and than it was expected to pass through the State House easily.

The legislature passed a similar measure last year barring investment of state funds in companies which operate in the apartheid state.

The Boston ordinance must pass through the legislature as a home rule petition because there are state guidelines covering the investment of pension funds. The ordinance applies to pension, housing and all other public funds, said George Brock, an aide to City Councilor Charles S. Yancey, who introduced the motion.

Boston currently has at least $10 million invested in companies with South African operations, said Brock, but he added that his office suspected the total to be much higher. The city treasurer has been directed to determine exactly how the new ordinance will affect finances.

At Harvard, activists have fought unsuccessfully for more than a decade to get the University to adopt a similar policy and divest from all companies operating in South Africa in an attempt to get the country to end its segregated apartheid system.