"We have fulfilled our legal obligations to 100 per cent."
But Mrs Mill said no one had spoken to them or any of the residents in the vicinity.
"I'm gutted and struck by the size of it."
Mrs Mill says she heard the original plans were to be a gymnasium.
But on Friday it had "escalated" when she saw the support structure being erected.
"I thought, what the heck is going on, it's a completely different concept," she said. "We have a beautiful lifestyle here, but this is 'think big'."
The land on which the events centre is built is a swamp in the winter which is why Mrs Mill says the structure was built closer to their property boundary.
The new building is 10-15 metres from the Mills' property boundary.
A 50-place carpark on their fenceline is also going to be built.
"There are enough under-utilised council buildings in Wanganui, why did the church have to build this?"
The residents are also concerned at the increase in traffic that will come with the new carpark, further disrupting the quiet of their country lane.
Another resident on Cathro Rd said they saw the concrete pad go down, but the sheer height of the building had upset them.
"It's very ugly, and we don't know anything about its use and the noise."
The residents are worried at the increased vehicle traffic on their road that already attracts double-parked cars on either side of the road when the school holds an event.
"We can barely get through, and when we try to exit on to Springvale Rd, the parked cars on the corner make it difficult to get a clear view; it's very dangerous."
Wanganui District Council principal planner Jonathan Barrett told the Chronicle that the council understanding was it was going to be a school hall, and had issued the consent because the "building of a school hall is a permitted activity in a residential zone and does not require a resource consent".
Mr Barrett added that there was awareness of drainage issues on the site and those had been factored in when the building consent was given.