New Zealand have been the world number one side for the entirety of Steve Hansen's spell in charge

New Zealand head coach Steve Hansen has announced he will step down after eight years in charge following the 2019 World Cup in Japan.

Hansen, 59, took over in 2011, having been assistant to predecessor Graham Henry since 2004.

Under Hansen, the All Blacks retained the World Cup title in 2015 and have won six out of seven editions of the Rugby Championship.

"This allows to us to get on and do what we have to do," said Hansen.

The New Zealand Rugby Union has yet to announce his successor and says it will not start the formal recruitment process until after the World Cup.

Since taking over from Henry following the 2011 World Cup triumph, Hansen has led the All Blacks to 85 victories from 96 matches - a winning ratio of 88.5% - with three draws and eight defeats.

"It's right for the team to have someone new after the World Cup, whether that's from within or without," said Hansen, who coached Wales from 2002 to 2004.

"It will bring a new outlook for the team and it'll be time for someone else to enhance the legacy of the All Blacks."

Hansen added he was "really pleased" about the timing of his announcement as it ensures he "won't be distracted by being asked every five minutes" about his future.

"I've still got the support of the rugby union and the backing of my players and I appreciate that.

"This allows us to concentrate on winning the World Cup and I'm really excited and motivated by that."

Assistant coach Ian Foster is a leading contender to replace Hansen, while fellow New Zealanders Joe Schmidt and Warren Gatland, who are leaving Ireland and Wales respectively following the World Cup, are also likely to be linked to the role.

"I think [Ian] would be a great head coach," said Hansen. "He has developed as a coach and a man and has some great qualities.

"But I don't think it's right that I say who should do the job. That is the union's job."

Hansen said the decision was also motivated by wanting to spend more time with his "brilliantly supportive" family and that he does not know what his next role will be.

"I don't know so don't ask me, but I'm not going to focus on what's next, the focus is on next year and trying to retain the World Cup," he said.

Analysis

BBC rugby union correspondent Chris Jones

Steve Hansen's record as New Zealand boss may never be bettered. Under his watch, the All Blacks have cemented their status as the best side in the world and have sat atop the world rankings for every single day of his tenure.

After winning back-to-back World Cups, Hansen's New Zealand can already lay claim to being the greatest rugby union team of all time; if they make it three in a row in Japan next year then there can surely be no debate.

Meanwhile, the coaching landscape come this time next year will be fascinating, with big hitters like Hansen, Joe Schmidt and Warren Gatland all set to become free agents.

The latter two will no doubt be linked to the All Blacks, as will younger coaches like Scott Robertson. However Ian Foster - Hansen's assistant - is considered the leading contender.