At present 2175 Martinborough ratepayers have been posted submission documents to have their say, and indicate whether they wish to fund the completion of the Waihenga Centre using targeted rates.
Submissions close on Friday.
Chief executive Paul Crimp said the $1.3 million was the "best estimate" based on information presented to council in August.
Around $500,000 has been spent so far on consultants and drawings, which made grant applications and a resource consent possible.
"We are confident the $6.4 million is the total bill."
He said council has locked in a fixed rate of 4.8 per cent for the loan.
"The rates would be set as part of the annual plan process next year.
"When we do the annual plan, we will know if the amount is $1.2 million, $1.3 million, $1.4 million."
He said an increase of $100,000 would mean about a $5 movement in the targeted rates. "We have come as far as we can. This project, as proposed, cannot go ahead without the targeted rate.
"If the targeted rate is not accepted, we have to consider other options." Mrs Staples said the process, started five years ago, came about because the hall needed earthquake strengthening.
The council was told that in order to attract grant funding, the building needed to be useful to Martinborough, with amenities, rather than a locked town hall used on occasion.
"Grant funders said they weren't interested in just the town hall [strengthening].
"The grants we have received are for the project as it stands.
"If we change that, all that money disappears, we go back to square one, the grants become null and void.
"We can't say, we're doing something smaller, can we have a bit less."
She also wondered if the hard work securing pledges would be threatened if the Steering Group had to start again.
"Council could have said, sorry, not enough money, we can't go ahead.
"But we felt we could go and talk to the community and see if they would support the missing bit."
While some council assets are being realised to foot the bill, council has never said it would sell Pain Farm, said Mrs Staples.
Sub-dividing a section of it was also not an option, as the funds have to go back to the farm estate.
She was asked if a close vote on targeted rates would be a go-ahead.
Mrs Staples said she suspected her councillors would want a clear mandate.
"If [the vote] came up with near to 50/50, they would say no."
The panel was asked why the wider district, and tenants, were not being asked to help fund it.
Mr Crimp said the only way was to ask the people who put their hands in their pockets and pay rates. "If they chose to pass that on to the tenant, that's up to them."
Ongoing maintenance costs, and running costs, would be a district-wide cost.
The panel was asked what the economic benefits of the Waihenga Centre would be.
"It's a community amenity," said Mrs Staples.
"But what has been shown, by the Carterton Event Centre, when you have a good quality amenity, more people want to use it, the people that live there, the people that come to it.
"It's about people you want to attract here.
"It's not about making money - if it was, we wouldn't have libraries."
Mrs Staples said an "enormous amount" of fundraising had already been done, including $825,000 of grant funding and $1.4 million in pledges.
She felt the community was "running on empty" with regards to more fundraising.
Asked if the project could be smaller, she said the proposal had been trimmed as much as it could.
"This is what Martinborough needs going into the future," she said.
"When you have a discussion on whether you support this project or not, give some thought around the use of the building.
"Think about the people you wish to attract to Martinborough, to make Martinborough a vibrant town."
"I've never heard anyone say to me, I shifted to a Wairarapa town because of a good sewerage system."
A result from the submissions would come late next week, Mr Crimp told the Times-Age yesterday.
