About 300 objections have been lodged against the £32m tourism development at Hamsterely Forest.
Forestry England submitted plans to install 70 cabins and hot-tubs, a new visitor centre, a Go Ape treetop adventure facility and a bunk house along with camping stands at the forest in November.
However, opponents began campaigning against the scheme even before the plans were unveiled.
Hamsterley Forest Action Group was formed earlier this year and has been lobbying neighbouring parish councils and other groups, such as the horse-riding fraternity.
The group has about 1,000 members on its social media site.
Campaigner Andy Richardson said the aim had been to generate 100 objections and was pleased that the target had been smashed.
He added: “It is good news and shows the depth of feeling people have for the forest.
“The planning application has left a lot of people asking questions. They [Forestry England] haven’t got the basic things right. People are asking where the sewage is going to, where the power is coming from, things like that.”
Among those to object to the scheme are county councillors Robert Potts and James Cosslett who represent Hamsterley.
Evenwood and Barony Parish Council has also written against the proposals and Mr Richardson said he expected parish councils for Hamsterley, Etherley and Woodland to follow suit.
He said the group had lobbied individual parish councillors on specific issues that affect their villages, such as the impact of traffic through Woodland and Toft Hill.
The group says the current road infrastructure is inadequate for the existing traffic and the situation would be exacerbated if the development goes ahead.
Campaigners say the single lane access to the forest is not a sustainable route to the proposed development, and was subject to flooding during Storm Bert in November as well as Storm Darragh last week.
Mr Richardson said: “There were five separate repairs done to the south of Redford Lane verge after subsidence and collapse.
“The repairs were made with stone filled gabions, and large concrete blocks.
“This is a clear road safety issue and a material planning consideration in regards to transport and infrastructure.”
Hamsterley Riding Association, which hosts a number of activities in the forest, has also opposed the development.
Helen Kirby, of the association, said: “There is a real lack of safe public places to ride in County Durham, especially for children, as the roads are becoming increasingly more dangerous to ride on.
“Losing Hamsterley Forest as a safe place would be devastating. There are hundreds of horse owners who specifically travel their horses to Hamsterley for that very reason.”
She added that part of the development is close to two car parks designated for horse-riding. “If these plans go ahead this will not be a safe place for horse-riding.”
Teesdale MP Sam Rushworth, while not objecting to the scheme, has urged county planners to “reflect local concerns”.
He highlighted, in particular, worries about the volumes of traffic going through Hamsterley and said the village would benefit from a 20mph speed limit and urged developers to mitigate environmental impacts of the project.
However, he shared his “sympathy with the need to raise revenue to fund a new visitor centre, café and classrooms at the forest”.
To date there have been two letters of support with Visit County Durham pointing out a lack of overnight accommodation in the county compared to neighbouring North Yorkshire, Northumberland and Cumbria.
“The tourism body had previously described the development as a “game changer”.
Outdoor and Sustainability Education Specialists (OASES), which runs school trips to the forest, also supported the application, saying the current facilities are limited and could only support small groups at a time.
The company said: “We feel that improved classroom facilities and a covered outdoor seating area would encourage more schools to access the trips we run at Hamsterley Forest and would improve the uptake of outdoor education.”
Cllr Cosslett said although the consultation period ended last week, the planning department would continue to accept comments until the application was considered by committee.
He added: “I am hoping that people will continue to send in their objection and I encourage them to do so.”
