Charamba declined to comment further when contacted on Thursday.
Two years ago, after the country was rocked by hyperinflation during the rule of former president Robert Mugabe, Mangudya introduced the surrogate "bond note" currency, supposedly pegged to the U.S. dollar.
Dollar shortages have caused prices of basic goods, taxis and medicines to rise in recent weeks.
The central bank chief has defended the use of bond notes, which have lost value against the dollar on the black market. He says a government budget deficit of 11.1 percent of GDP and a high import bill are the main causes of the U.S. dollar shortages.