Melbourne Storm backrower Tohu Harris has been cut from the Kiwis' World Cup squad to make way for Sonny Bill Williams.



After initially making himself unavailable for the New Zealand team, Roosters superstar Williams backtracked on his decision last night and reached out to national coach Stephen Kearney, offering his services for the tournament.



New Zealand's 24-man squad had already been named but a decision was made this afternoon to dump one-test Kiwi Harris to make room for Williams.

Harris said he was bitterly disappointed to miss out on being part of the eight-week tournament.



"As you would expect, I'm very disappointed not to be heading to the World Cup to represent my country," Harris said.



"I was very much looking forward to going, however I understand the decision that has been made and hope I get another opportunity to play for the Kiwis in the future."



Melbourne Storm Director of Football Frank Ponissi said the club shared Harris' considerable disappointment with the decision.



"We feel for Tohu in this situation given the range of emotions he would've experienced over the last 24 hours. He has had an outstanding first season of NRL and we know he would've done a wonderful job representing his country at the World Cup," Ponissi said.



"The NZRL invited Tohu to join the squad as part of the traveling party. Melbourne Storm, with the full support of Tohu, declined this opportunity to allow him to take a well earned break before returning for the 2014 pre-season."



World Cup organisers were notified of the New Zealand Rugby League's desire to change their initial 24-man squad and have signed off on it.



"It's been a tough situation, but Sonny brings things to the group that we couldn't ignore," Kearney said.



"He has had time since his NRL grand final win to clear his head and he wants to represent the Kiwis on the world stage.



"He missed our 2008 World Cup win and his inclusion will be a great asset in trying to repeat that success this year. It's not only his footballing ability, but also what he brings off the field which will benefit the team."



In a bid to limit Harris' obvious disappointment, the NZRL had wanted to take him to the UK in a development role and select him for the pre-tournament test against the Cook Islands.



However, the Storm felt it would be better for the 21-year-old to stay home and benefit from a full off-season.



"Tohu handled the situation as well as anyone could," Kearney said.



"It was a conversation no coach would like to have, but he's a terrific young man and I'm sure he'll have many more opportunities to pull on the black jersey. It's been a unique set of circumstances for all involved, but for now our focus is getting set to defend the World Cup with the team we have."