Dan Carter has revealed he needed some special inspiration to persuade him to push on to one last World Cup tilt.

Dan Carter has revealed that doubts about his ability to stay fully fit often led to him considering retirement.

In an interview with Seven Sharp on Friday, the World Rugby Player of the Year revealed that during his All Blacks career he often had periods where he didn't back himself.

"(I had) this huge sort of self doubt, whether I was good enough and it just increased. The more I held it in, the tougher I got."

He said he would listen to critics jumping on his back, and combined with his constant nagging injuries, that would often lead to him thinking: "Why don't I just quit now?"

He told Seven Sharp there was even a time when his relationship with All Blacks coach Steve Hansen had deteriorated to the point where they weren't talking.

"I just kept wondering why he would want to pick me, and I just assumed he wasn't going to pick me in the team."

He said he coped by talking to the All Blacks' psychologists, something that would probably have been frowned upon in the past.

Carter said his first kick after returning from the groin injury that ruled him out of the 2011 Rugby World was the hardest kick of his life.

"I was at the back of my run-up and for the first time in my life, I didn't want to kick the ball. All I could think about was whether my groin would hold up."

He said that the reality he was describing might not gel with public perception, because as a professional, he had learned how to put up a front.

"Being an All Black, you're perceived to be kind of robotic, these people who don't have emotions, these people who just go out and do their job."

Carter also told Seven Sharp about how he controlled his emotions during the Rugby World Cup in the United Kingdom last month.

He spoke about how in the lead-up to the 62-13 quarterfinal win over France, he and Richie McCaw decided that rather than dwell on the loss to them eight years earlier at the same stage, they would embrace the challenge head-on.

Before the final against Australia, he said he was "actually reasonably calm."

"I was in control of my game, I was in control of my thought process."

Carter kicked his last conversion in the 34-17 win with his right boot, rather than his usual left, something he told Seven Sharp he had always wanted to do before his international career came to an end.

He said the wrong-foot kick was his way of celebrating the win.

"After the final whistle, just a huge sort of weight on my shoulders was released and I knew that I could relax for the first time in ages."

"To be able to get to sign off on the biggest stage is probably one of the most pleasing things."

Carter's appearance was part of the promotion for his new autobiography, My Story, which is published on Saturday.

Next week he is set to leave for France, where he is set to become the world's richest rugby player with the Racing Metro club.