Pope Francis will skip a Mass on Sunday that he had been scheduled to say before his recent surgery, but the Vatican said there was no cause for alarm and that it was part of normal convalescence.

The Vatican said the pope will go ahead with his Sunday noon prayer but that a Mass for the Catholic Church day to pay homage to the elderly and grandparents will be said instead by Archbishop Rino Fisichella.

Vatican spokesman Matteo Bruni said it was part of "normal convalescence." Saying the Mass, which had been scheduled months ago, would have meant wearing vestments and alternating between walking, sitting and standing for about two hours.

The 84-year-old pope underwent surgery to remove part of his colon on July 4 and spent 11 days in hospital. He has been mostly resting since returning to the Vatican.

A papal trip to the Hungarian capital Budapest and Slovakia next month is still scheduled to take place, the Vatican said on Wednesday as it released a gruelling four-day schedule.