Pope Francis entered St Peter's Basilica in his wheelchair, took his place in a chair and offered up the opening prayer.

Sounding congested and out of breath at times, the pontiff blessed an Easter candle, the flame of which was then shared with other candles in the cathedral.

Over an hour later, Francis delivered a 10-minute homily in a strong voice, clearing his throat occasionally.

The evening service, one of the most important moments in the Catholic calendar, commemorates the resurrection of Jesus Christ and includes the baptism of eight adult converts to Catholicism.

The Vatican had said Francis skipped the Good Friday procession to ensure his participation in both the vigil service on Saturday night, which usually lasts for about two hours, and Easter Sunday Mass a few hours later.

The 87-year-old has been battling respiratory problems all winter that have made it difficult for him to speak at length.

The Vatican has said he has had bronchitis, a cold or the flu.

Francis, who had part of one lung removed as a young man, has cancelled some audiences and often asked an aide to read aloud some of his speeches.

Concerns were raised when he dropped his Palm Sunday homily altogether last week and then decided suddenly on Friday to stay home rather than preside over the Way of the Cross procession at the Colosseum.

The Vatican said the decision was made to "conserve his health".

Francis also skipped the chilly Good Friday procession last year because he was recovering from bronchitis.