Apart from the logistics required in getting a 32-player squad up to speed for a test on Saturday at Eden Park, a replay of the dramatic 2011 World Cup final, Hansen could be without playmaker Dan Carter and any number of props. There is also the matter of halfback Piri Weepu's concussion to attend to.
Carter has a cracked bone in his right hand, and only time will tell whether he will be able to play against the French. Hansen said the swelling around the injury was the main problem and the final decision might not be made until Thursday morning.
There is also a major question mark over loosehead prop Tony Woodcock, whose hamstring strain, which kept him out of the recent Highlanders' victory over the Blues, has been exacerbated by a painful abscess on his nose.
Tighthead Owen Franks hasn't played for the past fortnight due to a hamstring strain, with Crusaders teammate Wyatt Crockett also suffering a similar, but milder, complaint.
Tighthead Ben Afeaki has been laid low by a calf problem for some time, which leaves Ben Franks - who can play both sides of the scrum - as Hansen's only fully fit prop. Crusaders loosehead Joe Moody has been called in to provide scrummaging cover during training.
Although Hansen was optimistic his prop issues will be resolved, there is no doubt his pack's preparation will be compromised this week.
Carter suffered his injury during the Crusaders' narrow and fortuitous victory over the Waratahs in Christchurch. It was lucky for his team that he remained an active participant - his penalty from 49m with seven minutes remaining put the Crusaders in front for the first time in a win which has kept them in the play-off hunt.
"The biggest problem with Dan's hand is the swelling," Hansen said. "The biggest problem with swelling is you can't grip the ball. If that goes down well enough then he may well be all right to play. But until we let the swelling go we won't know that."
If Carter, the 31-year-old 94-test veteran described by Hansen last year as a "red-flag" athlete due to his increasing susceptibility to injury, is ruled out, the All Blacks are fortunate to have two in-form replacements in Aaron Cruden and Beauden Barrett.
Centre Conrad Smith summarised the feeling in the camp when saying: "Dan's had a few niggles in the past few years and we've dealt with it a few times.
"He's obviously a world class player with a lot of experience but there's a couple of 10s there who aren't doing a bad job at the moment so I think we'll probably deal with it better than we have in the past."
Carter missed the World Cup final with a groin injury, with Colin Slade, Cruden, and Stephen Donald playing a part in what was an excruciating 8-7 victory. Cruden's development over the past two seasons, plus Barrett's improvement, mean the All Blacks are far better placed to cover for his absence.
Hansen said Weepu's concussion had yet to be tested fully despite the halfback declaring himself fit after being knocked out during the Blues' loss to the Highlanders.
Hansen said Weepu's suggestion he was good to go had to be "taken with a grain of salt" because it "looked a pretty horrific injury".