The ANC Youth League warned ANC leaders on Monday not to defy the league's policy positions.
"Anybody who has taken a posture and has defined himself as against the ANC Youth League... such an individual runs the risk of losing the support of the youth league," its president, Julius Malema, said in Johannesburg.
This should not be seen as blackmail, he said after a meeting of the league's national executive committee at the weekend.
"This time around, we are not going to vote for those who are against Mbeki. This time around there is no Mbeki. The criteria now is (whether) we are we sharing the same perspectives," Malema said.
"It's not about personalities, it's about principles... We mean business. We are going to reduce everything else to paper."