A conservation lobbyist from Ruakaka, south of Whangarei, says it will be a disaster for the environment if the local racing club is allowed a commercial subdivision.
The Whangarei Racing Club is applying for a private plan change that would allow the building of 350 houses, and a hotel on land it owns at Ruakaka beach.
Margaret Hicks, a Forest and Bird member who is objecting to the plan change, says the site is just metres away from the high-water mark, and the proposal is inappropriate.
She says the Ruakaka Wildlife Sanctuary is just metres away and the godwits and dotterels that breed there would not survive the development.
"You can't introduce hordes of people into an area where periodically you get 2,500 godwits and where you get New Zealand dotterels nesting on the beach."
Mrs Hicks says the racing club and local horse trainers have already damaged the dune system and the rare dune lakes in the area.