Pope Francis voiced hope for a "fruitful and joyous" old age at a mass for his 80th birthday on Saturday, as he received messages of congratulations from around the world.

"Old age sounds ugly, and causes fear. But old age yearns for wisdom," he told dozens of cardinals at the mass in a papal chapel in Rome.

"Old age is quiet and religious, but also fruitful. Pray that mine will be that way, quiet and religious, fruitful and also joyous."

The Argentine pope received messages of congratulations from around the world for his 80th birthday, including at email addresses in eight languages specially set up by the Vatican.

"Italy is grateful to you for your constant closeness," said one from Italian President Sergio Mattarella.

"The pope's office is covered in drawings by children from the whole world celebrating his birthday," tweeted Antonio Spadaro, a Jesuit theologian close to the pontiff.

Spadaro released photographs of drawings showing a smiling pope with the world on his head or surrounded by children and party balloons.

But like almost every other day of his papacy, Saturday will be a working day for the holiday-phobic Francis.

Apart from the morning mass with the cardinals, he has meetings with Maltese President Marie-Louise Coleiro, several prelates and members of the Nomadelfia, a secular community that tries to live as the early Christians.

Despite the Pope not particularly celebrating his birthday - the Vatican came up with something more special.

The Vatican has released stamps of the Pope in panes of four.

A Spanish Raul Berzosa artist was commissioned to paint the picture of the Pope which was presented to the Pope ahead of his birthday.