Pope Benedict XVI was set to celebrate on Sunday an open-air Easter mass in St Peter's Square, followed by his traditional "urbi et orbi" (to the city and the world) blessing.
The mass and blessing beginning at 0930 GMT were due to be broadcast live in 57 countries.
On Saturday, Benedict baptised a former Muslim among seven converts to Roman Catholicism during an Easter vigil mass at St Peter's Basilica.
Saturday night's observance symbolises the passage of Jesus Christ from death to resurrection and is traditionally marked by adult baptisms.
Magdi Allam, a 55-year-old Italian journalist of Egyptian origin, is an editorial writer and deputy publisher of the Corriere della Sera newspaper.
He was long described as a moderate Muslim before he decided to convert to Catholicism.
"People who are baptised and believers are never strangers to each other," the pope said in his homily. "Continents, cultures, social structures and historical distances cannot separate us.
"But we meet each other, we know each other by the same Lord, the same faith, the same hope, and the same love that shapes us."
Allam, who has been outspoken about the conflict in the Middle East, in 2006 organised a demonstration in Rome in support of Christians in the Muslim world.
Benedict also baptised a Chinese woman in the Easter vigil.
"To the Catholic Church, anyone has the right to be baptised who is making a fully free choice after a deep personal quest and adequate preparation," Vatican spokesman Federico Lombardi said in a statement.
In its relations with Islam and other religions the Vatican has stressed both freedom of religion and the right to convert to another faith.
The two men and five women baptised on Saturday are from Italy, Cameroon, China, the United States and Peru.
About 30 cardinals celebrated the mass with Benedict, who seemed fatigued on the third day since Easter celebrations began in earnest on Holy on Thursday.
Friday night, the pope opted out of carrying a cross symbolising the crucifixion of Jesus Christ to conclude the traditional Good Friday procession at Rome's Colosseum.
The 80-year-old pope had planned to take part in the final three of the Fourteen Stations of the Cross commemorating the path Jesus took to his execution in one of Christendom's most solemn observances.
The theme of religious freedom was at the heart of that observance, marked by meditations penned by outspoken Hong Kong Cardinal Joseph Zen, a key figure for Asian Catholics including those in China who are split between the official and clandestine Catholic churches.