Auckland Regional Council chair Mike Lee is accusing the Government of doing a secret deal which would dramatically change the region's northern boundary.
Mr Lee believes the boundary will be moved south to around Waiwera - but the Government is not revealing its plans for the shape of the region just yet.
Prime Minister John Key says the Cabinet considered boundary changes about a week ago but he is not saying yet what they are and is warning people not to jump to conclusions.
The boundary change would reportedly slice through what is currently Rodney District and could cut 50 beaches and eight regional parks, moving them and residents to the control of more northern local authorities.
Mr Lee says it is a major change that has come out of the blue and is wondering what else has been decided in secret, when Aucklanders had thought the super-city changes were being dealt with out in the open.
"I find it absolutely incomprehensible that secret decisions should be made over probably what is one quarter of greater Auckland and none of us have been consulted," he says.
Mr Lee told Checkpoint on Tuesday public has a right to know what is being planned.
Rodney Mayor Penny Webster says it is the worst possible decision for those affected, who still do not know what is going on.