South Africa’s governing African National Congress (ANC) has upheld the expulsion of Julius Malema as the party’s youth league leader, a statement has said.

The ANC’s statement, released on Thursday, said: “In respect of the present disciplinary hearing, the [ANC National Disciplinary Committee of Appeal] NDCA confirms the sanction imposed by the NDC that the appellant be expelled from the ANC.”

He was banned from party activities in April after calling his former ally President Jacob Zuma a “dictator”.

Malema, 31, was suspended in November after being found guilty of three of the charges against him – including bringing the party into disrepute by calling for regime change in Botswana.

Speaking to Al Jazeera, Keith Khoza, an ANC spokesman, said: “We expect any member of the organisation who is in conflict with the constitution [to] correct themselves within the constitution and party.

“Julius Malema is what he is today because of the ANC.”

The NDCA also dismissed the appeal by the youth league’s spokesman, Floyd Shivambu, but rejected increasing his suspension from the ANC to five years, instead confirming it for three years.

The committee further rejected the appeal by Sindiso Magaqa, the secretary-general of the ANC Youth League.

“The appellant’s ANC membership is suspended for a period of one year, which shall come into operation with immediate effect,” it said

Last February, a panel rejected Malema’s appeal but said he could seek a lighter sentence.

The expulsion effectively curtails the career of Malema, one of the country’s most high profile politicians whose calls for a major transformation of Africa’s largest economy unnerved many investors and drew serious criticism from some ANC leaders.

Malema was elected president of the ANC Youth League in 2008 and played a key role in Zuma’s ascent to power in the 2009 election.