The comments reflect President Robert Mugabe’s displeasure at Zuma, who condemned events in Zimbabwe in unusually strong language at a regional summit last week.
"President Jacob Zuma’s erratic behaviour is the stuff of legends," the Sunday Mail said in an editorial. "The problem with Mr Zuma now is that his disconcerting behaviour has become a huge liability, not only to South Africa but also to the rest of the continent."
Along with the leaders of Zambia and Mozambique, Zuma demanded an end to the crackdown on Zimbabwe’s opposition which is blamed on Mugabe’s ZANU-PF party. In recent weeks, Mugabe’s security officials have cancelled opposition rallies and detained some rival figures, heightening tension before a possible general election this year.
The Sunday Mail is Zimbabwe’s main government mouthpiece and is unlikely to have published such comments, the strongest yet against Zuma, without official sanction.
The paper accused Zuma, the Southern African Development Community’s main Zimbabwe negotiator, of being a dishonest broker and of betraying Africa by voting for a no-fly zone over Libya at the United Nations Security Council.
"Mr Zuma’s duplicity is astounding. With such leaders, Africa is in mortal danger," the paper said in its attack on the president, who leads the African National Congress (ANC).
"The same President Zuma who voted for the bombardment of Libya is now speaking out against the use of military force by the United States, Britain, France and their allies. His ludicrous stance has left political scientists scratching their heads in puzzlement. Does South Africa have a foreign policy at all or has the ANC entered the era of Mickey Mouse posturing?"
Writing in the same newspaper, Jonathan Moyo, a member of Mugabe’s ZANU-PF Politburo said: "President Zuma is now tainted beyond recovery by the Libyan situation and his commitment to the African cause has become questionable."