WELLINGTON - Rugby World Cup winner Jerome Kaino confirmed on Friday he is leaving New Zealand to take up a two-year contract in Japan.

The 28-year-old loose forward, who helped the All Blacks win the Webb Ellis trophy for the second time, has exercised a clause in his contract that allowed him to leave at the conclusion of the Super Rugby season to join Japanese club Toyota, the New Zealand Rugby Union (NZRU) said.

Kaino has already been ruled out of all Super Rugby this season after undergoing shoulder surgery.

"JK has been a key figure in the All Blacks for several years now and part of the backbone of the side," All Blacks coach Steve Hansen said in a statement.

"He is a top man and I have been lucky enough to see him grow and develop over his years in the black jersey.

"He will be missed but we wish him ... all the very best, and we hope to see him back in New Zealand one day."

Several World Cup winners, including veterans Mils Muliaina, Brad Thorn and flyhalf Stephen Donald, who kicked the penalty that won the final for the All Blacks, had signalled before the tournament they would leave New Zealand.

Kaino, who has 48 test caps, is the first player since the tournament ended to confirm he was leaving.

The question of who will fill Kaino's position is already being debated with pundits suggesting All Blacks captain Richie McCaw could shift from the openside of the scrum to blindside. (Reuters)