Priests must abandon the "cudgel of judgement" when hearing confession, Pope Francis said in a homily to his specially appointed "missionaries of mercy" before their send-off yesterday.

The pontiff bemoaned that many abandon confession because they receive scolding or experience unnecessary prying from priests. Over 1,000 men were commissioned to preach about God's mercy during the Catholic Church's Year of Mercy, ending on 20 November. They will be sent to act as confessors for Catholics around the globe.

Around 700 attended the official papal mandate on Tuesday where Francis stressed they recognise that people's desire for forgiveness might be obscured by feelings of embarrassment about discussing their sins.

"It's not easy to go before another person, knowing he represents God, and confess one's sins," he said.

Confessors "aren't called to judge, with a sense of superiority", he said, but should be respectful and encouraging.

"Do not forget, there isn't a sin before you, but a repentant sinner."

The missionaries of mercy will be given special permission to absolve grave or uncommon sins such as abortion, which are normally dealt with by a bishop. They will travel throughout countries containing the Catholic Church's 1.2 billion flock, visiting places such as the United Arab Emirates, China, Burundi, Israel and Egypt.

One priest is travelling far into the Canadian north and another is using a camper van to reach Catholics living in the remote Australian outback.

"If you're going to the Arctic, bundle up!" the Pope joked.

The missionaries of mercy play an important role in Francis' Year of Mercy initiative to encourage a more welcoming and inclusive approach in the Catholic church. Candidates to be missionaries had to be "inspiring preachers of mercy" and "especially attentive to the difficult situations of each person".