Pope Francis has named a commission of inquiry to look into the activities of the troubled Vatican bank amid a new money-laundering investigation and continued questions about the secretive institution.

It is the second time in as many weeks that Francis has intervened to get to the bottom of the problems that have plagued the Institute for Religious Works.

On 15 June, he filled a key vacancy in the bank's governing structure, asking a trusted friend to be his eyes inside the bank with access to documentation, board meetings and management.

He has now named a commission to investigate the bank's legal structure and activities "to allow for a better harmonisation with the universal mission of the Apostolic See", according to the legal document that created it.

Francis has named five people to the commission, including two Americans: Monsignor Peter Wells, a top official in the Vatican secretariat of state, and Mary Ann Glendon, a Harvard law professor, former US ambassador to the Holy See and current president of a pontifical academy.

US cardinals were among the most vocal in demanding a wholesale reform of the Vatican bureaucracy and the Vatican bank in the meetings running up to the March conclave that elected Francis as Pope.

The demands were raised following revelations in leaked documents last year that told of dysfunction, petty turf wars and allegations of corruption in the Holy See's governance.

The commission is already at work and its members have the authority to gather documents, data and information about the bank, even surpassing normal secrecy rules.

The bank's administration continues to function as normal, as does the Vatican's new financial watchdog agency, which has supervisory control over it.

The announcement came amid a new embarrassment for the Vatican in which prosecutors from the southern city of Salerno have placed a senior Vatican official under investigation for alleged money-laundering.

Vatican spokesman Rev Federico Lombardi has confirmed that Monsignor Nunzio Scarano had been suspended temporarily from his position in one of the Vatican's key finance offices.

Msgr Scarano has said he did nothing wrong.

The Vatican bank was founded in 1942 by Pope Pius XII to manage assets destined for religious or charitable works.

Located in a tower just inside the gates of Vatican City, it also manages the pension system for the Vatican's thousands of employees.