Chief Executive Fabrizio Viola resigned as the Italian bank is working to complete a 5 billion-euro (4.23 billion pounds) capital raising needed to stave off the risk of being wound down.
"I am convinced that the appointment of a new chief executive officer (..) will strengthen the plan and will not modify it," Pier Carlo Padoan told reporters after a meeting of European Union finance ministers in Bratislava.
He said he was confident the plan will be successful and called for a quick appointment of a new boss.
The bank could hold a board meeting to name a replacement as early as Sunday, a source close to the matter said on Friday.
Asked whether the resignation of Viola may delay the bank's cash call, Padoan said: "the timing will be decided by the board together with the advisers that have to take into account of market trends".
He also said that the issue was not discussed by EU finance ministers during their two-day meeting ending on Saturday.
(Reporting by Francesco Guarascio; Editing by Alexander Smith)