Masterton Deputy Mayor Graham McClymont says a request to the Auditor-General by a group of locals to investigate the district council's civic centre project "is already being done".
A group of nine locals, calling themselves the Masterton Action Group, said they had contacted the chief auditor over the council's long term plan process.
"We want to know what process led to six Masterton councillors not even questioning the ongoing costs of an excessively expensive civic centre."
McClymont, chair of the project's working group, said he could "see cause for frustration" but cautioned against enthusiasm for "seemingly cheaper proposals".
In a letter to the Wairarapa Times-Age, McClymont said the group had the right to contact the Auditor-General, but that office had already approved Audit NZ to audit the current Long Term Plan.
"In other words, what you are requesting is already being done and you will get a response."
He said he could see cause "for frustration".
"However, a council and being a councillor is nothing like running a business or being a private developer.
"We operate under so much scrutiny and process it drives me crazy.
"I have had to learn patience and respect for process and procedure. It's not my natural space but I'm happy with the work we have done around infrastructure, the My Masterton campaign, and iwi representation and am frustrated by the failed three-council amalgamation.
"You win some and lose some."
He said the council had issues with developer-led projects in the past, citing the 2013 town square construction.
The square project, outside the existing town hall, had to be subsidised from council funds.
Significant cost overruns had to be "mopped-up with ratepayers' money", he said.
"The ground was left compacted and unprepared for plantings, killing the trees that were put in.
"Council were left to weather that media storm."
He said he would, therefore, caution against "enthusiasm for other seemingly cheaper proposals, as there is no guarantee they would come in on budget".
"Nor would they tackle the challenges we have. An under-resourced library, an archive with no safe place for its collection, rent to pay on a customer service centre and holding costs on a closed building.
"All issues that the civic centre project will address."
Mayor Lyn Patterson yesterday said she was "saddened" by the advertisement commissioned by the Masterton Action Group that was published in the Times-Age this week.
Councillor Tina Nixon was called out in the notice. She was one of six councillors to back the centre build.
In response, she supported her decision and said she wouldn't be "cowered by the Masterton Club Mafia".
Yesterday, a spokesperson for the Auditor-General confirmed the office was considering two complaints over the long-term plan.
Once the plan is approved by Audit NZ, it is set to be voted on by councillors on 30 June.