The initiative was sparked three years ago, when it became a "hazard" to take children down the cycleways because of the amount of litter being dumped, she said.
Together with their 29 tamariki- or "little eco warriors" - the centre's work toward sustainability has included edible gardens, solar power, upcycling and community clothing - as well as raising community awareness.
"It's in everything we do", Ms Mihaka said.
There had been incredible support from the community - they hold up to six clean-up events each year, their largest being one at Fernhill bridge where 80 people collected 1.5 tonnes of litter, and do a monthly event with Flaxmere College.
They are also moving toward permaculture to "leave things better than when you found them", Ms Mihaka said.
But they won't stop there. Future plans include producing a book for primary schools, no-wrap Fridays for lunchboxes, and to beat Auckland's Guinness World Record of the most people at a clean-up.
This is their second year as a finalist. If they win, the prize money will go toward their water conservation project to collect rain water for the children's use, Ms Mihaka said.
Other Hawke's Bay finalists include Havelock North for Most Beautiful Suburb, Hawke's Bay Farmers' Market for the Most Sustainable Business Project and Napier for the Most Beautiful City.
Hastings District's Flaxmere councillor, Henare O'Keefe, has also been awarded the Local Hero Award.
Mr O'Keefe - who will be MC at the awards - is the official Hastings Ambassador, and is greeted often by members of the community while he is out and about, the KNZB group said.
"He attends local events to engage with the community and can often be heard singing Hastings' praises - he is a fierce Hastings ambassador and does all he can to promote the region.
"Henare works tirelessly to build community, particularly in disadvantaged areas; with a purpose of reversing negative stereotypes and working against violence. His can-do energy and attitude is driven by his solid belief in the goodness of people."
¦To buy tickets for the awards evening, visit knzb.org.nz/award-conference-tickets/