"Not acceptable to me, nor to the constituents who expect me to be fully informed and persistent in my questioning of this project."
He asked the council's chief executive Liz Lambert when councillors would get to view the updated business case.
She said councillors had already received the business case for the dam in 2014.
"The focus of this peer review by Deloitte is on changes made to the business case since the previous review," she said.
When pressed for an updated report by the councillors, Ms Lambert said one did not exist.
"HBRIC Ltd have not produced an updated business case as a document - they are focusing on the CPs [conditions precedent]," Ms Lambert said.
She said Deloitte was working on information provided to them by HBRIC.
Mr Belford said he found it "outrageous" that after $20 million worth of development HBRIC could not, or would not, produce a written business case that councillors and interested members of the public could examine and evaluate to their own satisfaction.
He said the 2014 version was so out of touch with current realities as to represent a fantasy, and provided no basis for an assessment of the project.
Ms Lambert said the council acknowledged that there would likely be some amendments to the business case along the way.