"I have letters from architects and designers who are charging the CHB factor, which can be an additional $3000 to $20,000, to put a consent through CHB, something they are not doing with other authorities," Mr Watts said.
"The cost to get the right answer for this shouldn't be a factor.
"A lot of letters that have come to me are from ratepayers who have spent money on consents - not just builders - it would be good to reach those people, as they are no less important."
There was also discussion over the confidentiality of the letters and the importance of assuring people any complaints would not be seen by building department staff.
Committee member and deputy mayor Ian Sharp said there were worries that the submitters would be vetted as to who would be included in the audit, and concerns over who would see their letters.
"People are very wary about their personal grievances being shared with those people their grievance is with."
Chief executive John Freeman said the staff would not see any of the correspondence.
Mr Butler said Morrison Low would receive all the letters where people had given permission to be included.