A $520,000 gap between income and operating costs will see Horowhenua ratepayers financially supporting the new Foxton museum, gallery and community centre complex after it opens on November 18.
Latest figures from Horowhenua District Council show the Te Awahou Nieuwe Stroom development will have annual income of $133,000 and operating costs of $651,000.
HDC has said the operating costs are budgeted in its annual plan.
HDC chief executive David Clapperton said the figures were in line with HDC's funding policy for libraries and community centres, with operational costs having a targeted rate of 75-85 per cent and fees and charges making up 15-25 per cent.
"The Te Awahou Nieuwe Stroom budget is to ensure that this amazing community facility, which will be a major visitor destination, is [part of] the social infrastructure and a community gathering space for residents and visitors," Mr Clapperton said.
Foxton Beach resident Christina Paton said the district could not afford to provide so much money.
She said a previous financial indication from HDC was that the annual shortfall would be around $200,000.
In July, HDC received a $1 million grant from the Ministry for Arts, Culture and Heritage to go towards construction of the building.
A condition of that grant was that HDC would agree to fund reasonable maintenance, operating and staff costs for exhibition and gallery spaces.
Mrs Paton said the word 'reasonable' put a lot of liability on HDC to cover costs.
A former HDC councillor, Anne Hunt, said she was assured as a councillor when the museum's trust deed was first drawn up that council would not be liable for operating costs for the museum part of the facility.
"We need to be assured we are not going to have a run-away budget," Mrs Hunt, speaking as a member of the public, told the HDC meeting last month.
"I'm stunned and shocked," she said this week, after learning of the half million dollar shortfall.