Tararua District Council made a provision of $52,000 for 2017/18 to build two additional cabins for the site, and the Cunninghams recently requested that this money be used to install more toilets instead.
Eketahuna Community Board supported this request but council chief executive Blair King said the budget provision would not be sufficient for additional toilets, "particularly when it is unclear whether the septic tank system is capable of handling the extra volumes".
The Cunninghams have managed the grounds for more than three years and have brought success to the site, winning the title of Supreme Winner of the Camping Grounds category in last year's Top Ranked Awards New Zealand.
She said she "just can't believe" that more toilets are unlikely to be added.
"We're bringing money into the town and everything.
"Our visitors come and spend money in Four Square, and takeaways, so why the council is not doing it, I don't know," she added. "I just can't believe it.
"They say it could be in the future plans and long-term planning, but we actually need it now.
"Tourists are coming to Eketahuna especially and we want to build this place up, we don't want to have to turn anyone away."