More than 20 areas are in the line to become national parks, according to the Ministry of Natural Resources and Environment.
They include seven forest and waterfall areas that were approved for the upgrade by the National Park Committee at a meeting on Tuesday.
Deputy permanent secretary for ministry Wijarn Simachaya listed them as Khelang Banphot in Lampang, Namtok Buatong-Namphu Jed-si in Chiang Mai, Namtok Phacharoen in Tak, Kaeng Jed Kwai in Phitsanulok, Sankalakiri in Songkhla, Namtok Sipo in Narathiwat, and Na Yung Nam Som in Udon Thani.
The permanent secretary will forward the committee's approval to the cabinet for consideration, Mr Wijarn said.
Attendees at the meeting were informed by officials from the Department of National Parks, Wildlife and Plant Conservation that the seven areas are among 23 seeking endorsement to be listed as national parks, covering 4.5 million rai in total, said Songtham Suksawang, director of the National Parks Office.
One of the remaining 16 areas, Tham Pha Thai in Lampang, is having its case handled by the Council of State, which is examining a royal decree endorsing the area as a national park, Mr Songtham said.
Once the decree has been vetted by the Council of State, it will be given to the Secretariat of the Cabinet, which will forward it to the King for endorsement should it get that far, Mr Songtham added.
Another three were approved in principle by the cabinet and the decrees are to be delivered to the Council of State for examination, the director said. They are Doi Jong in Lampang, Nanthaburi in Nan, and Than Sadet-Mu Koh Phangan in Surat Thani.
Mai Klaipen Hin petrified forest park in Tak is in the process of having a decree drafted.
Another three are having their respective cases forwarded to the cabinet for consideration. They cover Mae Tho in Chiang Mai, Khanom-Mu Ko Thale Tai in Nakhon Si Thammarat, and Ao Siam in Prachuap Khiri Khan.
The eight other areas are also being checked to see where their exact boundaries are and whether they fit the criteria for inclusion. They include Ao Manao-Khao Tanyong in Narathiwat, Phu Pa Ya in Udon Thani, and Lam Nam Kok and Phu Cheepha in Chiang Rai.