A West Coast primary school is backing up sugar education with action.

Barrytown School is the first school on the Coast to commit to water and milk only on campus, going fizzy free in a West Coast District Health Board pilot programme.

Principal Rachael Whyte says kids are learning how good water is for their bodies - compared with the amount of sugar that's in fizz and orange juice - and she says it's having encouraging results.

"Kids are choosing water and milk at home over fizzy and stuff, which speaks volumes as to what they've learnt and how they are taking it on board and incorporating it not only at school but at home as well."

Whyte says being a small school of about 26 students away from town and without access to canteens or shops has helped, as has the support of parents.

A public health worker leads a weekly interactive educational class around water, sugar and your body.

Whyte says she thought the kids would kick up a fuss - but that hasn't happened.

"The biggest issue we've had is convincing our staff that you can't bring your Coke into school cause we're a water and milk school now. The kids have just taken it and run with it."

A local dentist is in support of the move, and says the level of tooth decay he's seeing is disturbing.

Greymouth dentist Garry Rae has been practicing for 40-years on the coast and says while school dental nurses intercept chronically bad tooth situations, what he's seeing in High School students is concerning.

"A lot of corrosion, a lot of erosion, which is from fizzy drinks, and that is a bit disturbing."

He likens it to a car washed in salt water.

"If you have a car, and you washed it every day with salt water, it would rust. If you take it to the panel beater and have the rust taken out, but are still washing it every day with salt water. This is what we're facing."

Rae says education is what's needed to curb the huge amount of sugar-related tooth decay.