Steve Hansen may be the overwhelming favourite to succeed Graham Henry as coach of New Zealand but iconic All Blacks skipper Richie McCaw is not rushing to congratulate him just yet.

Hansen was appointed assistant All Blacks coach in 2004 and served an eight year apprenticeship under Henry during which time New Zealand were the most consistently successful team in international rugby.

His term as an assistant to Henry alongside Wayne Smith culminated in the "three wise men" guiding the All Blacks to their first World Cup title in 24 years on home soil this year, and with Henry stepping aside after finally lifting the Webb Ellis Cup it has been widely accepted that Hansen has the inside track to take over when the new coach is revealed in the middle of December.

Despite the perception that Hansen's appointment is "a done deal" already, the New Zealand Rugby Union (NZRU) have been at pains to stress that they will consider a range of candidates for the post with current Clermont boss Vern Cotter emerging as a late dark horse.

McCaw, who brought up his century of Test caps for New Zealand in the pool match against France at the World Cup, has plenty of respect for Hansen but he believes that it would be foolish not to consider all the potential options properly before making a decision.

The All Blacks are the best team in the world and McCaw believes that it is crucial that they have the best coach in order to ensure that they stay ahead of the chasing pack.

He told Fairfax media: "People say it's a done deal, but I don't think it is because you need to see the best out there. If Steve's the best that's great, but you need to figure that out.

"To keep the All Blacks as being the best in the world, they've got to have the best men available. Whoever that is, is up to the guys making that decision to find out," added the All Blacks captain.

It should come as no surprise that McCaw's top priority is the wellbeing of the team he has served with such distinction over the years, and the continuity that Hansen's appointment would represent may be exactly what the world champions need.

"If it is Steve, then that's great because he has been a part of a successful team, he knows what works and I'm sure he'd add to that with some slightly different ideas, but would also keep some of the good things that have worked to," said McCaw.

After working closely with Hansen for the past eight years McCaw has developed a good relationship with the former Wales boss, and he does not believe that would change much if Hansen is indeed appointed as head coach.

He commented: "I always get on pretty good with him. The thing about Steve is that you can have some pretty good discussions about the game. We think quite alike on things. Probably not the same on some things, but he'd do a good job, there's no doubt about that.

"He's been through the lessons that Graham and myself have been through, but I think for the All Blacks they need to get the best man available and that's why they're going through the process," McCaw explained.

Former Crusaders assistant coach Cotter was thought to be out of the running after recently signing a contract extension with French Top 14 club Clermont, but he has revealed that he has a "get-out clause" which has seen him installed as Hansen's biggest challenger.

McCaw confirmed that he would not be opposed to Cotter taking the reins either, as he has fond recollections of his time with the Crusaders.

"He was assistant for a couple of years and we won the thing twice so I have pretty good memories of that team," he said. "He has done well over in Clermont too and has a pretty good record. It will be interesting. He is a good man."