The electronic petition set up by Banfield, at publication time, had 272 signatures calling for the meeting's project discussion to instead be open.
"They are saying the meeting is 'commercially sensitive'. We say 'no way!'," Banfield said.
"Commercial interests cannot override open transparent decision-making," Banfield said.
FNDC chief executive Blair King told Local Democracy Reporting it was not feasible to open the meeting to the public.
"I appreciate the request to have the meeting in Paihia to enable further feedback on the merits of works. Given this agenda report is on the tender and ability to meet the associated MBIE (Ministry of Business, Innovation and Employment) funding agreement, it is not feasible to open that discussion to the public," King said.
"Councillors will be receiving tendered supply prices/rates within the extraordinary meeting agenda. It is for this reason that we must place the report within the public excluded part of the agenda," he said.
The Government in 2020 put $8m towards the project. FNDC last winter signed off on paying the $5.845m balance.
The waterfront storm mitigation project aims to protect Paihia, a favourite New Zealand tourist spot where giant storm waves have caused about $1m in foreshore damage over the last 20 years. This is expected to triple over the next two decades.
Carter and nine councillors will have to formally vote to move into public excluded ahead of starting their discussion.
The agenda recommends they vote to do so via a resolution which lists the reasons for the move and includes specific grounds for doing so under the Local Government Official Information and Meetings Act 1987 (LGOIMA).
The recommendation said the reason for passing the resolution was identified in the agenda as being that witholding the information being addressed was necessary to enable FNDC to carry on, without prejudice or disadvantage, negotiations including those of a commercial and industrial nature.
The grounds for passing the resolution were listed as the public conduct of the relevant part of the meeting proceedings would be likely to result in disclosure of information that had good reason to be witheld, under the LGOIMA.