The department has sent back the airport plan proposed by the southern province, saying further studies are needed in at least three areas.
Department director-general Chonlatid Suraswadi on Wednesday pointed to the need for the province to assess the environmental impact of the project, present the agency with the views of residents who will be affected by or are opposed to the plan, and for more inspections of the proposed location.
"The Royal Forest Department has returned the proposal to the provincial governor," Mr Chonlatid told the Inside Thailand news programme on Spring News TV. "The proposal still needs an Environmental Impact Assessment and views from the other side," he added.
Bangkok Airways has approached the province, wanting to build an airport in Thai Muang district.
An area of 2,000 rai in tambon Lam Kaen in the district has emerged as the potential site, after an earlier site was found to include part of Klong Tung Mapro reserve deemed "degraded forest land".
The tambon Lam Kaen council voted in May last year to support the plan and provincial authorities also backed it, pointing to expected benefits to the province from tourism and trade. The provincial governor then sent the proposal to the forest department.
The future of the airport apparently rests with the department, as it controls the land in question.
"The pictures attached to the proposal show that the land has some green spots," Mr Cholatid said, but said the department had not jumped to a conclusion it was degraded forest land.
Forestry officials in the province would re-check the location to confirm its status and the department would send officials from Bangkok to look into the area, Mr Cholatid added.
The airport project has divided local residents into two camps.
Supporters welcome the plan to build an airport in the province because it would mean not having to travel to Phuket to catch a plane, and it would assist tourism.
Opponents say the land slated for the airport's construction is not deteriorating forest land, and have accused Lam-kaen Municipality of too hastily holding a meeting to support it.
