Exercise NZ chief executive Richard Beddie has defended gym classes for children, saying that calls for kids to be outside more or to play sport aren't helpful.
Mr Beddie said less than 10 per cent of Kiwi children do enough physical activity, with gyms and community groups starting to offer classes targeting children in response.
"Children is 10 per cent, that means in the future we're going to have some major problems with obesity and type 2 diabetes for that population, we already have that," Mr Beddie told TVNZ1's Breakfast,
"This is part of the solution for that and having some offerings for children to be active."
Mr Beddie said the fact we had this issue meant calls for more sport of more outside time for kids were redundant.
"If it was easy as that we wouldn't have the problem in the first place," he said.
"The problem with saying they should be outside ... it’s clearly not working, we need to change something, playing outdoors is part of the solution just as exercise activity in a class might be part of the solution."
"The problem with sport is it appeals to certain people, particularly those that have a competitive element, but sport actually turns a whole bunch of people off."
"Simply saying it should be all about sport, it's a very 20th century solution to the problem."
Gym classes, in which Mr Beddie said kids didn't squat or bench press, were often convenient with children exercising as their parents did.
"Generally, one of the big benefits of this, it can be done at the same time as adults are exercising, cause that's part of the challenge too, we need to be active, if you've got kids part of the challenge is where do I take them or what do I do when I'm working out."