"We have one shot at this. It is the chance in a lifetime for this city and its citizens to work together to get the right plan in place," he said.
Mr Green said it seemed that the plan was already set in concrete because of the depth of financial details.
Councillor Gail McIntosh responded that they had no choice but to get down to the nuts and bolts because of audit requirements.
Mr Green said the council had presented fancy pictures and lovely computer generated fly-throughs, but very little about creating a city heart.
"It did however create the perfect vision of a city hall that is over-scaled for the amount of council staff."
He said the mass of buildings in the plan "intimidated the city heart and had no relationship to the actual physical space or human interaction''.
Mr Green also questioned where the 480 plus council staff would park their cars.
"We know that a new parking building is to be built in Harington St, but by the time it is leased out, there would be next to nothing left for anyone else - as is the case in existing car park buildings."
"Just when you try to turn the city around, you stop the very people you are trying to attract from having some place to park."
Mr Green said another flaw in the plan was there had been no consideration about the future of the bus transport hub.
"One has to wonder what end the council had in mind when it started this project...this is not exactly the master plan that we all expected."
Local government specialist Peter McKinlay said the council would be making a decision little more than a month out from the election.
''In practice, this means the present elected members are proposing to hand a fait accompli to an incoming council. Much the better option is for the present council to recommend to the incoming council.''
Mr McKinlay said creating a liveable, people friendly CBD was of greater long-term significance than the details of new accommodation for the council.
"This should have been emphasised in council's consultation. Before proceeding with any decision, the council should set out its vision for the future development of the CBD."