Vice-President ConstantinoChiwenga said the nurses had refused to return to work after $17m (£12m) was released to increase their pay.
He chided them for not going back “in the interest of saving lives”.
But the extraordinary move may simply be a tactic aimed at forcing the nurses back to work, correspondents say.
Reviving the health sector has been a key challenge for President Emmerson Mnangagwa, who recently agreed to pay rises in order to end a doctors’ strike.
“Government has decided, in the interest of patients and of saving lives, to discharge all the striking nurses with immediate effect,” said Gen Chiwenga – the former army chief who led the overthrow of long-time leader Robert Mugabe in November – in a statement.
He said unemployed and retired nurses would be hired to replace those who had been sacked.
In response, Zimbabwe’s nurses’ association said it “taken note” of the move but added that the nurses remained on strike.