The Sunday Independent reports that books and files were taken from his office, and his former personal assistant Moshala Mothiba's computer was stolen, from Luthuli House in central Johannesburg, apparently while the ANC was holding its policy conference in Midrand.

"The incident happened while the people were at (the policy) conference," police spokeswoman Inspector Lorraine van Emmerik told the newspaper.

She said police were investigating a case of business robbery.

The paper quoted unnamed sources saying that the door had not been forced open, and that the computer contained information on the daily running of the league.

Malema was expelled from the ANC earlier this year and barred from entering any of the party's offices.