Pope Francis has made his first public appearance in more than five weeks, waving from a balcony at Rome's Gemelli hospital. He was discharged from the hospital a few minutes later.

The 88 year old was admitted to hospital on February 14 with a severe respiratory infection that became the most serious health crisis of his 12-year papacy.

The pope's doctors said on Saturday that it would still take "a lot of time" for his body to fully heal, and said they had prescribed the pontiff a further two months of rest at the Vatican.

After saying goodbye to hospital staff, he returned to the Vatican to begin his rehabilitation and convalescence, during which time doctors have said he should refrain from meeting in big groups or exerting himself.

On the journey back to the Vatican, the Pope made a surprise stop at St Mary Major Basilica, where he goes to pray after foreign visits. He didn't leave the car, but handed a bouquet of flowers to a cardinal to place in front of a favourite icon of the Madonna.

He was seen in the front passenger seat of the motorcade, wearing oxygen nasal tubes.

Francis' stay in hospital is the second-longest in recent papal history.

Over the last five weeks hundreds of people have gathered outside the Vatican and the hospital to pray for his recovery.