Incumbent President Jacob Zuma has warned that there would be no jobs for friends in his new Cabinet, as criticism within the African National Congress (ANC) mounted against some of the newly chosen Premiers.

"There will be no favours and there are no friends. Those not put in government must not cry," Zuma told a rally at Zwide in the Eastern Cape on Sunday.

The ANC president said being a friend of his was not a guarantee to a government job, The Star newspaper reported.

Zuma, whose ruling party failed to secure a two-thirds majority in the April general elections, said he would not tolerate incompetence.

"Those who are chosen must not feel they are above the rest."

Zuma, who is expected to name his Cabinet within the next few days, last week announced the nominated Premiers to each province, notably choosing Gauteng's housing MEC, Nomvula Mokonyane, over the widely expected choice, the current Premier, Paul Mashatile.

The ANC Youth League has called on the party to reconsider its decision and appoint Mashatile, who took over from Mbhazima Shilowa, a cofounder of ANC breakaway party the Congress of the People.

The ANC in the Northern Cape has also complained about its provincial chairperson, John Block, being sidelined in favour of Bo-Karoo mayor Hazel Jenkins.

But Zuma said the ANC leadership in each province had put forward three candidates for Premiers and that the national executive committee was free to choose any of those candidates.

"Provinces should understand whoever is appointed must be supported by the structures, so I don't understand who in the provinces are now making a noise about their first preference.

"If three names are submitted and we choose one, we are allowed to choose any one of them," said Zuma, who will be inaugurated as South Africa's new President on Saturday.