A group of fishermen and Karen villagers plans to petition the National Council for Peace and Order (NCPO) to address concerns over what they see as "intimidation by influential people".
The group, comprising about 50 representatives from several provinces, including Phuket, Ranong, Kanchanaburi and Phetchaburi, are expected to travel to Bangkok to submit the petition soon.
Saengsom Hantalay, a resident of Satun's Koh Lipe, said local fishing communities have been intimidated by influential people and many residents have been forced to leave the island after threats were made.
She said their predecessors had settled on the island more than a century ago, but authorities later declared the area as a national reserve, triggering a long-standing dispute, which was resolved after officials allowed them to stay on the island.
Ms Saengsom said the fishermen later came into conflict with investors who wanted to use the land the villagers occupied for tourism businesses.
Many residents were intimidated and forced to move out, she said. Some of the villagers were deceived into signing land ownership transfer documents, she said.
She called on authorities to examine whether these investors possessed proper land ownership documents that had been obtained legally.
Maitree Jongkraijak, a representative of a local fisherman network, said the number of fishermen inhabiting coastal provinces along the Andaman Sea in the west had dwindled to about 12,000.