Eight bodies have been recovered so far from the abandoned camp in Sadao district, in Songkhla province, a few hundred metres (yards) from the border with Malaysia.
The grim discovery has once again exposed Thailand's central role in a regional human trafficking trade.
Four shallow holes in the dirt a short walk behind the camp mark where the bodies were retrieved, an AFP reporter at the scene said, while white ribbons tied to a few dozen bamboo poles delineated suspected new graves.
Doctors treating the two sole survivors -- men aged 25 and 35 -- told AFP their patients were suffering from a range of ailments.
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"Both are malnourished, have scabies and lice," doctor Kwanwilai Chotpitchayanku told AFP at Padang Besar hospital.
"The older man could not walk, he had to be carried off the mountain. He hadn't eaten anything for two days before he was found. He told the translator he had a fever in the jungle for two months."
Both were rigged to IV drips and appeared frail as they lay in their ward beds.
The border zone with Malaysia is criss-crossed by trafficking trails and is notorious for its network of secret camps where smuggled migrants are held, usually against their will, until relatives pay up hefty ransoms.
Rights groups say the camp, which is a steep, slippery 40-minute hike from the nearest road, is likely to be just one of dozens in the area as the rewards of trafficking continue to outweigh the risks of being caught.
Tens of thousands of migrants from Myanmar, mainly from the Rohingya Muslim minority but also increasingly from Bangladesh, make the dangerous sea crossing to southern Thailand, a well-worn trafficking route often on the way south to Malaysia and beyond.