South Africa's deputy president is urging state prosecutors to target suspects in corruption scandals, some of whom have been linked to a business family with close ties to President Jacob Zuma.

Deputy President Cyril Ramaphosa said in Johannesburg on Thursday that he wants prosecutors to "act with urgency and increase the tempo" in their work to curb graft that has hurt the South African economy and the popularity of the ruling African National Congress party.

Ramaphosa, who replaced Zuma as ruling party's leader in December, travels next week to the World Economic Forum meeting in Davos, Switzerland. He says he will deliver a message that South Africa is "deadly serious" about fighting corruption.

Scandals linked to Zuma and the Gupta business family have sullied the president's tenure in recent years.