The assets were being held by four banks and security companies in South Africa, reports quoting Libyan investigators say.
Some estimates suggest that Gaddafi`s total foreign assets could be worth as much as $80bn.
Gaddafi was captured and killed as he tried to flee his home town of Sirte during Libya`s political uprising in October 2011.
Any assets belonging to him or his family are firmly considered by many Libyans as state-owned property that should be returned.
"There was a group that approached Treasury claiming to represent the Libyan government and we are in the process of verifying their claims about assets that are in South Africa," a spokesman for South African Finance Minister Pravin Gordhan was quoted as saying by South Africa`s Sunday Times newspaper.
Libyan embassy official Salah Marghani said that officials had "been appointed to investigate and secure assets in Africa on behalf of the people of Libya".
The newspaper printed extracts of letters from Libya`s justice and finance ministers to their South African counterparts asking for help finding assets linked to Gaddafi, which might "have been illegally possessed, obtained, looted, deposited or hidden in South Africa".
It said Libyan investigators had met Mr Gordhan and President Jacob Zuma to discuss locating and returning the money.