But she said the plan needed to be brought forward, and quickly.
"The church itself is actually getting overrun with the sheer volume of visitors. I was down there at lunchtime yesterday and there were five large buses, plus campervans, plus cars.
"It's beautiful, and it was stunningly beautiful yesterday, and they all want to come and see it. They all want to get their photographs of this unique church and it's open. You walk up to it and walk around it."
Images of the church often feature in travel brochures and New Zealand Government marketing overseas.
Ms Sweney said New Zealand needed to take better care of it.
She said freedom camping was prohibited in the area, but the odd person stayed overnight.
It was not the worst location for freedom camping issues in Tekapo, she said.
"The volume of tourists in Tekapo has exploded exponentially and the forecasts are that they are going to keep coming."
She is urging the Government to limit freedom camping in the Tekapo area.
"There is quite a significant number of people coming through who expect everything for free. That's the reputation New Zealand has. So we do need to take the free out of freedom camping and have low-cost camping areas where people can go."