The NZRU has relaxed its rules to clear the way for Sonny Bill Williams to slot straight back in for the All Blacks when he returns to rugby union later this year.

Williams, who is completing his second stint in the NRL, would normally have had to participate in New Zealand's NPC before being eligible for All Blacks honours. But an exemption has been made, allowing Williams to play on the world champions' end-of-year tour to the United States and Europe.

Williams began his career in rugby league, winning the 2004 NRL title with the Canterbury Bulldogs in his debut season before controversially walking out on the team mid-contract to play rugby union in France.

He was equally successful in the 15-man code, contributing to the 2011 World Cup win by the All Blacks and snaring the 2012 Super Rugby title with the Chiefs, before returning to the NRL with the Sydney Roosters last year, picking up another title with the side.

Williams's return has been timed to reinforce the All Blacks before they defend their World Cup title in England next year.

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