The All Blacks feared allowing a documentary crew to follow them throughout last year would result in the loss of the secrets that make them what they are.

American company Amazon Prime will from next week screen a six-part documentary made with the assistance of the All Blacks after head coach Steve Hansen and his management, and no doubt senior player group, agreed to allow their television cameras and producers behind-the-scenes access.

The filming for the series, titled All or Nothing: New Zealand All Blacks, includes interviews and images from the often controversial drawn series against the British & Irish Lions last winter.

New Zealand actor and director Taika Waititi narrates the documentary which promises to give viewers an insight into what the first trailer describes as "the team with the highest winning record in the world".

Hansen, in Christchurch preparing for his team's final camp before the first test against France at Eden Park on June 9, today revealed the tension behind the decision.

The All Blacks, more so than most international rugby teams, are notoriously secretive about their methods, with security guards and high walls now commonplace at training runs. The defending world champions have been the No.1-ranked team in the world since 2009.

"There was a lot of debate about it," Hansen said. "But we're a rugby nation that doesn't have a big commercial background supporting it.

"Amazon reach a massive audience. It's about enhancing the All Black brand I guess, the opportunity to do that. All the risks and rewards were weighed up and in the end we decided to do it. Once we decided that then it was in boots and all and do it the best we can."

Hansen is recorded in the trailer telling his players on a training pitch: "You've got to start working harder – we've brought you here because we believe in you."

He said he had seen the film's final cut, adding when asked if he was happy with it: "I don't know if I'm happy with it or not but it's not really for me to be happy about it. Amazon paid for it so as long as they're happy... I think we've managed to keep most of our IP [intellectual property] safe, but it will be interesting for some people to watch, yeah."

Asked about whether it was a realistic portrayal, Hansen said: "I think so, pretty much. In any of those circumstances there's a little bit of guarding going on isn't there? You don't want to tell the world all your secrets. I mean, you work hard to get where you get to. I wouldn't say it's a 100 per cent true reflection because it never will be – no matter which organisation you go into.

"We've been as honest as we possibly can be without giving away too many secrets."

Hansen said the players were supportive of the decision and it was in no way to blame for the drawn series against the Lions. He said there was "not too much" that the All Blacks objected to in terms of filming.

"They wanted it to be as realistic as possible so you might hear a bit of swearing from time to time but that's normal life in a rugby team."