South African President Cyril Ramaphosa said on Thursday that he did not believe Chinese investments in Africa were pushing the continent into a "debt trap" but were instead part of a mutually beneficial relationship.

Ramaphosa made the remarks on the sidelines of a China-Africa summit in Beijing, where delegates from more than 50 African nations gathered this week.

"I don't necessarily buy the notion that when China (invests), it is with an intention of ... ensuring that those countries end up in a debt trap or in a debt crisis," Ramaphosa said, when asked by reporters about China's pledge at the summit of $51 billion in new funding for Africa.

Without providing details, Ramaphosa also said South Africa had reached agreement with China on aspects of its energy security.

Africa's most industrialised economy has been plagued for years by rolling power blackouts that have constrained economic growth.

(Reporting by Joe Cash; Writing by Tannur Anders and Bhargav Acharya; Editing by Alexander Winning)