Steve Hansen's all-conquering reign as New Zealand head coach will end after the 2019 World Cup.

The 59-year-old Hansen has been involved with the team since 2004, first as an assistant to Graham Henry and then as head coach from 2012, and fashioned an unrivalled record in the professional era, having won 85 of his 96 games in charge.

Hansen told a packed news conference in Auckland that he had decided to make the announcement now to avoid their World Cup build-up being disrupted by questions about his future.

"I'm finishing," Hansen said. "I just think that after 16 years it is the right time to move on after the World Cup. It is the right thing for the team.

"Fresh eyes, fresh thinking and I think that will be great in the enhancement of the legacy of the team."

Hansen said he had not thought about his future beyond the next 12 months. Local media reported that he might take on a director of rugby role with New Zealand Rugby (NZR).

"What's next? I don't know. So don't ask," he said.

"I'm not focusing on what's next. I'm just focusing on next year and retaining the Bledisloe Cup and winning the World Cup for a third time in a row."

NZR chief executive Steve Tew said they might consider retaining Hansen in another role, but that conversation would not take place until after the World Cup.

Hansen had signed a contract extension in 2016 to keep him in the role until March 2020.

Yet prior to that he said he felt it was better if a coach stepped down mid-way through a World Cup cycle with his successor having been part of the team's set-up.

Leading contenders to replace Hansen include Wales coach Warren Gatland, who is returning to New Zealand after the World Cup, Hansen's assistant Ian Foster and Canterbury Crusaders coach Scott Robertson.

Joe Schmidt, who announced he will step away as Ireland head coach after the World Cup, had been touted as a likely successor, but said last month he will "finish coaching" to focus on his family.

Tew confirmed earlier this week that the All Blacks wanted Schmidt to replace Wayne Smith as Steve Hansen's assistant in the summer of 2017.

It was mooted he would work alongside Ian Foster, with one of them ultimately taking over from Hansen, but Schmidt turned down the offer.