Iwi, surfers and boaties have occupied the site of a marina in the Coromandel town of Whangamata in protest at the development.
About 20 protesters pitched tents, set up barbecues, and camped at the site overnight in a low key occupation.
They have received an equal amount of toots of support and abusive yelling from passers-by.
The occupiers are also opposed to the relocation of endangered moko skink lizards from the site by the Department of Conservation.
Maori Party co-leader Tariana Turia said the occupation was about trying to protect the history and cultural values of the area.
"They've had an ancient saltmarsh destroyed in order to build a car park, and there's been the destruction of habitat of several rare and threatened coastal bird species (and) the moko skink."
Iwi say construction of the marina will threaten the natural coastline and sea life because of dredging on the river channel.
The Whangamata Marina Society says the project will continue despite the protests.
"We'd certainly resist any attempts to stop it," society president Mick Kelly told the Waikato Times last week.
The moko skink, classified as "sparse" by the Conservation Society, were found just a month before excavations were due to start on the marina site.
The work follows a 14-year campaign by marina backers which involved extensive legal action.
It is understood that work on the marina was due to begin yesterday but so far no developing equipment or workers have turned up.
- With NZPA