Dr Smith said sports and flavoured drinks and caffeinated beverages were a problem among children.
"I would say that considering that they don't need sugary drinks or sports drinks for sports, then I think it is a problem," she said.
"Children are faced with marketing that sends them mixed messages about what's required for sport and certainly the food and nutrition guidelines in New Zealand at that level of activity say they only need water to rehydrate."
Dr Smith said children were consuming empty calories, potentially creating cavities and causing numerous poor health outcomes that were largely preventable.
The children said electrolyte sports drinks were part of their sport-related diets but Dr Smith said kids didn't need them for extra energy or rehydration.
"These are only needed by athletes playing high level or elite sport."
She said implementing healthy food and drink policies in sports clubs and promoting tap water as a free choice for sport would be ideal solutions.
"Other strategies including healthy eating and drinking programmes in sports clubs, and nutrition education and dietary advice for children, parents and coaches, would also be beneficial."
Garry Carnachan, the executive director of the New Zealand secondary schools sports council, said the problem with heavily marketed sports and caffeinated drinks wasn't solely an issue on sports fields.
He believed sports teams at secondary school level were more likely to provide water but it was up to parents what they sent their kids off to their sports games with.
"I actually don't think it's just a sports issue, you'll see kids drinking these things walking down the street.
"It's a marketing issue and if the incidence has increased at sports it's probably increased everywhere else as well."
NZEI Wellington branch president Charles Bisley said schools promoted healthy choices and actively discouraged children from drinking caffeinated and sports drinks.
But he said outside of school it was difficult to monitor.
"We are concerned for the whole education for the kid, not just their literacy and numeracy, and I think all teachers would make a big effort to make sure their kids in their class are healthy and make good choices," Mr Bisley said.
The study also showed excessive packaging and serving sizes were common, and there was evidence of a need to regulate portion sizes to reduce energy intake.
Dr Smith said given the global nature of food, drink and sport, the situation in other countries is likely to be similar.
New Zealand ranks fifth in the OECD for childhood obesity with a third of New Zealand children currently either overweight or obese.
Ranui Tiger puts plain water in her tank
Every Saturday morning during winter 8-year-old Christina Hellesoe laces up her boots and plays football for the Ranui Tigers.
Her mum Niu fills her drink bottle with water straight from the tap.
"It's just plain water, no flavoured water or Powerade or anything like that, just straight water."
Photo / Supplied
Mrs Hellesoe said most of the players' parents followed the same line and brought their own drink bottles filled with water.
"Parents in general that I know are very conscious not to give their kids sugary drinks," she said.
"There's the messages through school and the dental nurses - I can't ever remember seeing a child on a field with a can of Red Bull - they're hyper enough as it is so it is a bit of a concern if it's happening."
