The Herald on Sunday has reported Sonny Bill Williams has made a spiritual conversion to Islam.
Williams converted two years ago, before he returned to New Zealand to play rugby, and requested halal food during the All Blacks' northern hemisphere tour last year, the newspaper said.
Friends said he regularly attends Friday prayer sessions at a Christchurch mosque.
Federation of Islamic Associations of New Zealand first vice-president Javed Khan told the Herald Williams' allegiance was commonly known among the Muslim community.
"He is practising the religion and he is a great role model for the youngsters. We will pray to Allah that he will win the World Cup for us. Everyone talks about it, you know. The Muslim community, everyone knows everyone, you know."
Williams' manager, Khoder Nasser, and mentor, league star and boxer Anthony Mundine, are both Muslim, as is his brother, Johnny, who lives with him in Christchurch.
All Black manager Darren Shand said the player's religious beliefs had a "minimal" impact on the team.
"He has talked to us about his dietary needs ... We request halal beef and so on, but he doesn't make a big deal of it," Shand told the newspaper.
"We always leave players' religious affiliations and a lot of those holistic things outside of the game. That's their personal life and they decide what they do."
Asked if his faith clashed with the All Blacks' philosophy for encouraging players to be free-thinking and self-reliant, Shand said Williams was a "sponge" for information.
"That's why he is so good at all the sports he has been involved in. He just ticks all the boxes. He wants to be the best."
