Pope Francis has met senior colleagues in hospital to discuss work issues, the Vatican said on Tuesday, and an official said he was eating normally and moving around, even though he remains in critical condition with double pneumonia.

The 88-year-old pope was spending his 12th day at Rome's Gemelli hospital, the longest hospital stay of his nearly 12-year-old papacy.

"The pope rested well all night," the Vatican said in a one-sentence statement that did not provide further details.

A Vatican official, who did not wish to be named because he was not authorised to discuss the pope's condition, said Francis was eating normally, moving about his hospital room, and continuing his treatment.

The Vatican said Francis had met his second-in-line, Cardinal Pietro Parolin, and Parolin's deputy on Monday.

It said they had discussed several pending cases for sainthood. The Vatican also announced new appointments that would have needed the pope's approval.

Francis has been working occasionally from the hospital as Vatican business continues apace during his illness.

The pope's only other known VIP visitor was Italian Prime Minister Giorgia Meloni, who visited him on February 19.

On Monday, the Vatican said the pontiff's condition remained critical but had shown a "slight improvement", adding that a "mild kidney insufficiency", first reported at the weekend, was not a cause for concern.