An appeals panel of South Africa's ruling ANC on Saturday upheld a decision to expel its firebrand youth leader Julius Malema for bringing the movement into disrepute, sending into the political wilderness one of the leading voices for nationalising mines.

The decision will derail the career of Malema, 30, one of the country's best known politicians whose calls for radical transformation of Africa's largest economy unnerved investors and drew harsh criticism from some African National Congress leaders.

It will also likely silence Malema's calls, at least in the short term, for a state takeover of the mining sector in the major commodities producer, analysts said.

Malema's fate has been increasingly tied to President Jacob Zuma, whose path to re-election as leader of the ANC at the end of this year could be blocked if the party rebel, an ANC power-broker, is still in the movement.

The appeals panel upheld Malema's conviction on bringing the party in disrepute and causing rifts in the group but turned back for further deliberation a decision on how long the suspension will be.

Malema cannot escape suspension under ANC rules.

Discipline is one of the key pillars in the life of the ANC, Cyril Ramaphosa, senior ANC politician and head of the appeals committee, told a nationally televised news conference.

Malema was found guilty by the disciplinary committee in November and sentenced to a five-year suspension. The committee will hear testimony for mitigation of its sentence in two weeks.

Malema is also facing a criminal probe that is looking into his finances. He has been able to stay in the party pending the appeal.

Malema will be stripped of his position as president of the ANC Youth League and ostracised by the party which dominates South African politics.

(Reporting by Jon Herskovitz and Olivia Kumwenda, editing by Rosalind Russell)