Mutambara is trying to wrestle back the control of the smaller MDC formation after he was toppled by Ncube at the party’s congress in January.
After initially accepting defeat, the robotics professor made a U-turn and is now backing aggrieved party members challenging the Industry and Commerce minister’s victory in the courts.
Sources said Mutambara also wrote to the president of the Senate Edna Madzongwe saying Ncube must cease being a senator.
Mugabe and Madzongwe have reportedly not acknowledged getting the letter but Tsvangirai has already done so.
Maxwell Zimuto, the spokesman for the group challenging Ncube’s presidency said only Mutambara and Joubert Mudzumwe had the mandate to make such communication.
Both their phones were not reachable yesterday. But Ncube dismissed the move by Mutambara, if true, as a non-event.
“No we have not received such a letter, it’s not possible, and someone has to be a lunatic to do that,” he said.
“It can’t possibly exist. You will need people that are certifiably insane to write that.”
However, Tsvangirai’s spokesperson Luke Tamborinyoka yesterday could neither deny nor confirm whether the PM had received the letter.
Mugabe’s spokesman George Charamba also said he does not know anything about the letter.