New Zealand's bishops have issued a message of solidarity with the country's Muslims after mosque attacks in Christchurch that left at least 49 people dead.

In the message, they wrote: "We hold you in prayer as we hear the terrible news of violence against Muslims at mosques in Christchurch. We are profoundly aware of the positive relationships we have with Islamic people in this land, and we are particularly horrified that this has happened at a place and time of prayer.

"We are deeply saddened that people have been killed and injured, and our hearts go out to them, their families and wider community. We wish you to be aware of our solidarity with you in the face of such violence."