The competition will be judged at next month’s Sustainability Festival.
Co-organiser Alice Brice said outfits were to be made out of 75% recycled materials.
Mrs Brice said entries were $5 for primary-aged children, $10 for high school students and $20 for adults.
She said a lot of things were planned for the festival, including "inexpensive" workshops for children, families or adults alone.
One of the workshops was non-chemical weed management, which would be run by an agri-ecologist.
There will also be workshops for electric vehicles, guided tours of the wetlands, and propagating native plants with Felicity McMillan, of Arowhenua Nursery.
Mrs Brice will run a Nature Ninja course, targeted at saving the birds. She said it would cover predator trapping and "allowing the birds to flourish".
A quiz night will be held on Saturday, November 9, while the fair will be held on the Sunday.
One of the stall holders booked in was Eco Youth, which hoped to sell a variety of things including predator baits and a pottle of toothpaste powder which was aimed at reducing toothpaste packaging.
Organisers were accepting stall holders for the event and would be grateful for donations for raffle prizes.
A repair cafe will coincide with the event.
Mrs Brice said the festival was a "chance to be inspired".
"It’s all about celebrating possibilities."
