Sportal.co.nz 15.Nov.2013Getty Images
Carter will be the fifth All Black to play 100 Tests, behind Crusaders team-mate Richie McCaw, hooker Keven Mealamu and prop Tony Woodcock of the team of the moment and former fullback Mils Muliaina.
"Any All Black to be able to sustain a career long enough to play 100 games is a special player but he [Carter] is probably one of the special, special ones," Hansen said.
Injuries since the Rugby World Cup in 2011 had been frustrating for Carter and had denied him the chance to reach 100 before this weekend. However, he expects Carter will be capable of playing a complete 80 minutes if necessary against England.
Hansen is in a unique position to assess Carter's career. He was on the receiving end of his debut game when coaching Wales.
"The very first [Test] he played was pretty sharp."
Carter appeared at second five-eighths, outside Carlos Spencer with Tana Umaga at centre. He scored a try, kicked six conversions and a penalty goal in New Zealand's 55-3 win at Hamilton.
"I happened to be coaching the opposition, he scored 20 points. He played very, very well," he said.
Carter continued to play at second five-eighths, with the odd substitution at first five-eighths, and it wasn't until his 15th Test, against Italy in Rome in 2004, that coach Graham Henry, and now selector Hansen, entrusted him with the starting role at first five-eighths. He celebrated with a try and seven conversions.
In the remaining games of the tour he established himself in the position with an outstanding contribution to a 45-6 hammering of France at Stade de France in which he scored a try, kicked four conversions and four penalty goals for a 25-point haul.
That set the scene for the following year and what Hansen said was probably his best game was the second Test against the [British and Irish] Lions in 2005 – that stands out. Carter scored 33 points in the game which sealed the series for New Zealand as they won 48-18.
"I thought his [roundrobin] game against France in the World Cup in 2011 was outstanding, it looked like he was going to have a great impact on that tournament until he got injured," he said.
That groin injury sent tremors through the nation but New Zealand's depths of five-eighths were tested before Stephen Donald filled the gap in the final with his match-winning penalty goal.
But there have been other frustrations, most notably the torn Achilles tendon suffered while playing for Perpignan in France in 2009 while this year he suffered a broken hand to miss the June Tests against France and he suffered a shoulder injury in Bismarck du Plessis' tackle against South Africa at Auckland.
Yet Carter has kept bouncing back and in his absences two contenders to eventually replace him, Aaron Cruden and Beauden Barrett, have emerged.
Hansen said: "We're very fortunate we've got a young man who's becoming world-class in Crudes, and we've got another young player in Barrett who's not far behind."
Carter goes into his 100th match as the greatest points scorer in Test history at 1435 points, made up of 29 tries, 255 conversions, 254 penalty goals and six dropped goals. Of the 99 Tests he has played the All Blacks have won 87, lost 11 and drawn one giving him a win percentage of 88.38.
And in 10 Tests against England, one of which was lost, he has totalled 171 points from four tries, 26 conversions and 33 penalty goals.
2013 Air New Zealand European Tour - Steve Hansen Press Conference 10868 views