Pope Francis was said to be awake and cheerful Wednesday after undergoing a three-hour hernia operation which has revived concerns over the 86-year-old's increasingly fragile health.

The Argentine pontiff had been admitted earlier in the day to the Gemelli hospital in Rome, where he is expected to stay for several days, AFP reported.

"The Holy Father reacted well both to the surgery and the anaesthesia. He is already awake... he has already cracked a joke," the surgeon who operated on him, Sergio Alfieri, told reporters.

All papal audiences have been cancelled until June 18 to give the pontiff time to recover.

The Vatican press office said the operation "went without complications and lasted three hours".

The pope, who underwent colon surgery in 2021, was suffering from a hernia that was "causing recurrent, painful and worsening" symptoms, Vatican spokesman Matteo Bruni said earlier.

Francis had looked in good spirits as he led his weekly general audience at the Vatican on Wednesday morning, waving to the gathered crowds as he did a round of St Peter's Square in his popemobile.

He then left for the hospital in his white Fiat 500 car, escorted by police.

Francis was suffering from an incisional hernia on the site of a scar from a previous surgery, Alfieri said.

He was placed under general anaesthesia and the abdominal wall was repaired with a surgical mesh.

All the pope's audiences have been cancelled "as a precautionary measure" until June 18, the Vatican press office said.