Last week, Wanaka Watersports Facility Trust chairman Michael Sidey said the "whole community was on board now" as construction of the facility was about to begin.
But the Save Wanaka Lakefront Reserve Group has disputed that claim.
In a statement from president Alan Cutler and secretary John Coe, the group said Mr Sidey's comments had "absolutely no factual basis".
"Furthermore it is insulting to the many residents and users of the lakefront who continue to be disappointed and distressed by this `insensitive development'," the statement read.
"A substantial number of locals and visitors were, and still are, horrified at the prospect of cutting down attractive mature trees on the lakefront and replacing them with a large utility building.
"We can assure Mr Sidey, the public, and the numerous people who provided financial support to protect the lakefront from inappropriate development, that we remain implacably opposed to the site chosen for this building and any claims to the contrary are totally erroneous."
