Pope Francis has said the troubled Vatican bank must become "honest and transparent" and that he will listen to the advice of a commission he has set up on whether it can be reformed or needs to be shut down altogether.

The pope made his comments, his most detailed to date on the bank's troubles, in his first news conference, a remarkably frank 80-minute meeting with reporters night shortly after his plane left Brazil at the end of his first international trip.

“I don’t know what will become of the bank. Some say it is better that is a bank, others that it should be a charitable fund and others say close it,” he said.

The bank, formally known as the Institute for Works of Religion (IOR), is the target of several investigations by Italian magistrates on suspicion of money laundering.

“We have to find the solution,” Francis said. “But whatever the solution, it must have transparency and honesty. That’s the way it must be,” he said.

Francis said he trusted those working at the IOR and trying to clean it up as well as a five-member commission he set up to advise him on the future of the bank, which has been the source of embarrassment and scandal for the Church for decades.

The comments came as the Vatican confirmed its Financial Information Authority (AIF) had signed a memorandum of understanding with Italian authorities over the exchange of financial information to combat money laundering in line with international standards.

The Vatican has already signed similar agreements with other countries, including the United States but the latest move is significant because of the high volume of transactions that go through Italy.

Reuters