Green is the best and red foods - which include cakes, confectionery, fats and soft drink - are not recommended.
John Bollard, chairperson of Avondale Community Preschool, said New Zealand daycares had to follow Ministry of Health guidelines on healthy food.
He said it was imperative that children learned healthy eating when they were young for not only their own health, but also to ease the pressure on the country's health system.
"They've got to eat healthy otherwise they won't last the distance. They will get overweight and have heart conditions and all of that."
However, parents had to accept the centre they signed their child up to had rules as well.
"It's probably hardly a hanging offence but I wouldn't be offended if the childcare centre sent a note home, but on that basis she would have to desist, wouldn't she."
He said it wasn't unusual for rules to be in place about what food could be brought along but he said there also had to be a balance before going "over the PC top".
"She probably made a mistake based on the rules for the childcare centre because they can make their own rules."
If it happened at his childcare centre he would expect one of the teacher's to have "a quiet word" with the parent.
Nicole Roe, of Evolve Educare - formerly Lollipops - said their daycare centres have their own policies, however most of them promoted the Heart Foundation's healthy heart policy.
She said if a child brought something unhealthy to a centre she would expect staff to have a quiet word.
Healthy Food Guide nutritionist Claire Turnbull supported the daycare's healthy eating stance and believed New Zealand needed to be more in line with how the Australians operated.
She said it could be debated "until the cows come home" about the nutritional value of the chocolate slice, but parents had to adhere to the daycare's rules that they agreed to when they enrolled their child there.
The nutritional value of pre-packaged food was sometimes easier to determine than something cooked in a kitchen at home, she said.
Turnbull, who has a 2-and-a-half-year-old boy in daycare, said she often provides home baking for her toddler, but she specifies what it is. She was also tactful about the ingredients she used, including tahini instead of butter, and seeds instead of nuts.
She also gave her son unsweetened yoghurt with his own fresh fruit to go in it.
"There needs to be better support in daycares to help them tell parents; 'this is accepted and this isn't accepted'."
She said "stacks" of nutritionists were graduating without jobs and suggested the Government hire them as advisers at preschools.
Maree Stewart, chief executive of Waikato Kindergarten Association, said their centres were part of the enviro-school initiative, which encouraged healthy eating.
"In our centres, because we provide the food, we have heart-tick meals and the children have to have so much fruit and milk each day. We encourage it and we discourage people from sending chips and chocolate but you do have to have that balance."
They did allow special treats for birthdays, she said.
The scheme also promoted minimum waste, which discouraged the use of food wrap, and the association was also in partnership with Sport Waikato's Under 5 Energise programme.
Early childhood worker Susannah Newton said the centre where she worked had a healthy food policy with lunchbox guidelines that included a list of banned food.
"If we find these foods we ask the child to not have it at preschool; rather, take it home and have it there. We are constantly educating the tamariki and the parents about healthy food choices. We even have alternatives on standby in case the child has no other healthy options. We send a wee note home that asks for the item not to be in the lunchbox, which also refers to our healthy food policy and healthy heart award."
However, her centre did not refuse home baking, she said.
