"It is tantamount to tearing apart the unity government," MDC spokesman Nelson Chamisa told AFP.
The state-run Herald reported Wednesday that Mugabe was pondering replacing MDC ministers who have not attended cabinet meetings since Prime Minister Morgan Tsvangirai cut ties with Mugabe’s ZANU-PF after a deadlock over key issues.
"His Excellency may have to consider appointing ministers in an acting capacity to key ministries for the sake of a successful agricultural season and general economic turnaround," Agriculture Minister Joseph Made told the Herald.
"Important Cabinet decisions have to be translated into action expeditiously," he said.
Chamisa slammed Mugabe for acting outside the spirit of the global political agreement (GPA), which has been hampered by a deadlock over key appointments on which Mugabe insists and by a crackdown on MDC supporters.
"That is a laughable proposition. This is precisely the reason why we are deadlocked. They are in a mode of unilateralism and arrogance which has not helped the spirit of the GPA," Chamisa said.
"You cannot appoint an acting minister when there is a substantive minister. It will create a parallel government," he added.
The unity government, created in February a year after disputed polls, is in deep trouble and hopes are pinned on a meeting by the Southern African Development Community (SADC) security organ Thursday to resolve the latest impasse.
"This deadlock will have to be broken. SADC and the AU (African Union) as guarantors will have to break this deadlock. It is in the interest of all of us," said Chamisa.
The MDC has accused Mugabe’s ZANU-PF of spurious arrests, and said Tuesday that the party’s transport manager Pascal Gwezere had been abducted and arrested hours after a similar attempt on another party member.