A Manukau City councillor is questioning the process for gathering some of the submissions in favour of a whitewater rafting course and cultural centre.
Submissions have been received from 18,000 people in support of the proposal by the Pacific Event Centre, which wants $40 million from the council to partly fund the project.
Manurewa councillor Daniel Newman says he understands some of the supporters are school students who may have been asked to sign support forms as they entered and left school.
He is not sure all those who support the project are fully aware of the financial cost and would like to hear an explanation from Pacific Event Centre representatives.
The centre's chief executive, Richard Jeffery, says each submission form clearly outlines the cost to ratepayers.
He says construction costs will add 48 cents a week to the average Manukau rates bill, but will also create jobs for the community.