The 29-year-old is also contemplating offers from clubs in Italy and Japan.
Maxwell only returned to New Zealand rugby during last year's National Provincial Championship competition after taking a year out to travel and allow his body to recuperate from the rigours of almost 10 years of first-class rugby.
The Canterbury and Crusaders lock did enough to earn a place on the All Blacks end of year tour to Europe but his efforts meant he missed the first three rounds of the Crusaders' Super 12 campaign with a sore back.
The second rower, who has played 36 Tests for the All Blacks, is now on the sidelines after surgery on a broken and dislocated finger and is considering his options, with the All Blacks' Test series against the British & Irish Lions looming.
"Norm Maxwell would play for the All Blacks if he was capable of playing," Henry said.
"He is trying to ascertain whether his body will enable him to stay in international rugby.
"Norm Maxwell is not running away from New Zealand to play overseas. He is a passionate All Black and he wants to play.
"He is going through mental gymnastics at the moment trying to work out whether he can get to a level where he can play international rugby and he's struggling with that."
He added: "Some of the media have got it wrong who think he is going overseas to make money rather than play for the All Blacks.
"Norm Maxwell is passionate about playing for the All Blacks and would do that if he was capable of doing that. As far as I know he is still going through the mental process of trying to make that decision. We'll know in due course and I'm not panicking about that."
Should Maxwell decide to head overseas it would leave a big hole for Henry to fill with a shortage of experienced locks to partner Chris Jack in the second row.
Keith Robinson has yet to return to action after surgery on his back and Ali Williams played his first match in six weeks on Friday following his suspension for stamping on Richie McCaw.
It could mean Highlanders rookie James Ryan, who has had an impressive debut season in the Super 12, or Hurricanes' Ross Kennedy get thrown into the international fray.
Maxwell's last match was for the All Blacks in their 45-6 win over France in Paris last November.