South Africa's ruling ANC put off discussions planned for Monday to bring its Youth League leader Julius Malema to heel after the populist politician angered the party by calling for nationalisation of mines and meddling in foreign affairs.

Analysts said the African National Congress may try to temporarily silence the outspoken Malema but it will be difficult to keep down a man expected to be a power broker when the ANC elects its top officials at a party gathering next year.

The ANC and Youth League met briefly on Monday and decided to postpone further discussions because of the complexity of the issues, an ANC official said. Party sources had said at the weekend the talks would focus on friction between the two sides.

Malema's call to nationalise mines and seize white-owned land has unnerved investors but struck a chord with poor blacks who make up the majority of the population and who envision him as a future leader of Africa's biggest economy.

"There are people within the ANC frustrated with what the Youth League is doing, but they see a benefit to the Youth League's support and will keep quiet even if it is possibly damaging for the county or the party," said Lucy Holborn, research manager at the South African Institute of Race Relations.

The ANC, which prides itself on keeping its squabbles internal, blasted the Youth League for its call to overthrow the democratically elected government in neighbouring Botswana.

"The African National Congress would like to totally reject and publicly rebuke the ANC Youth League on its extremely thoughtless and embarrassing pronouncements on "regime change" in Botswana," it said in a statement.

ANC brass last week slapped down Malema's calls for nationalisation, saying they are hurting the economy.

Malema in recent weeks has faced charges that could derail his career, with major papers reporting he has a slush fund for bribes used to pay for his lavish lifestyle.

The Youth League accused white capitalists of a conspiracy to bring down Malema, saying the family trust fund on which media reports have focused is used to finance charitable work.

Malema, 30, has no direct policy-making power in the ANC but his ability to influence the masses of poor puts him in an influential position, with senior leaders including President Jacob Zuma courting him to secure their political aspirations.

Malema's call for nationalising mines would bankrupt South Africa, economists said, with many seeing it as a ploy to help his allies obtain bailouts for bad investments they made in the sector.

Even though nationalisation could send the economy off a cliff, the ANC has kept the topic alive by saying it requires further study, so as not to alienate Malema.

The market capitalisation of listed mining firms in South Africa is about $270 billion, equal to about two-thirds of GDP or twice the annual national budget.

Threats to tweak laws in order to expropriate shares for a fraction of their value would run up against international investment guarantees that would almost certainly trigger severe backlashes from South Africa's trading partners.