"It's a concern," Henry said in an interview with Newstalk ZB's Tony Veitch to be aired today.
"We haven't played South Africa yet, but they got beaten by Australia and they are woeful. I think it's probably the worst Australian team I have ever seen and that's a real worry for the game.
"You want Australia playing rugby and you want Australia playing well. And you want South Africa to be doing the same thing. But South Africa have probably lost half of their tests over the last three years.
"Australia looked okay at the [2015] World Cup but have fallen away badly this year. We really need these sides to be competitive to create interest in the game and bring crowds."
The All Blacks played in front of sellout crowds in Wellington and Hamilton and AMI Stadium in Christchurch will also be full tonight, but there were 22,000 empty seats in Brisbane last weekend to see Australia beat South Africa 23-17.
The phenomenal form of and style of rugby the All Blacks are playing is attracting interest but there are concerns it could become monotonous if they remain well ahead of the rest of the world. The All Blacks' record against South Africa of 53 wins from 91 meetings since 1921 - a win ratio of 58 per cent - is their lowest against all traditional rivals but they have won 11 of their last 13 meetings.
Their policy of picking New Zealand-based players only means the best remain in this country, in contrast to the policy adopted by both South Africa and Australia.
"I think the All Blacks team need to continue with their [winning] attitude," Henry said. "They won't worry about any of this talk, and rightly so. Steve, Kieran [Read] and the group will continue to strive to get better and play their best game of the season in Christchurch. That's the culture of the team.
"The general supporter who likes great games of rugby has some concerns, and rightly so.
"In New Zealand, everything is in place for the All Blacks to be the best they can be, but in South Africa, there are major political issues [in the game] and in Australia, you have three other sports seen as bigger than rugby and, if they don't win, guys are not going to play [the sport]."
The All Blacks seem to have taken things to a new level in 2016, an impressive achievement a year after a World Cup and in a year after a number of personnel changes. Henry, for one, is surprised.
"I wondered whether they could step up another level after Richie [McCaw] and his band of merry men who retired together [moved on] but they have.
"The team - coaches and players - look at it and say, 'how can we step it up another level?' If Richie, Conrad [Smith] and others were there, I'm sure they would have done the same thing. I don't think it's necessarily the new players [who have helped take it to a new level] but a team wanting to get better. That's what drives them, getting better every day and every season. "
In the Bledisloe Cup test in Sydney, the All Blacks made 241 passes, including 28 offloads (the Wallabies made 139 passes and six offloads), and the skill-set across the whole team has improved. The sight of props Owen Franks and Joe Moody offloading in the tackle, creating space for Beauden Barrett and Ben Smith, would be enough to make any opposition envious.
"I think they have been phenomenal," Henry said of the All Blacks. It certainly differs from his assessment of their traditional rivals.
