Police and military representatives made announcements and leafleted Cambodian workers at the Rong Klua market in Sa Kaeo's Aranyaprathet.
The authorities ruled out the possibility of rounding up alien workers.
However, hundreds of Khmer workers continued to leave the province for Cambodia.
Thai authorities and vendors at the market tried to create a friendly atmosphere with Cambodians by staging concerts, handing out food and drinking water, and deploying more than 10 trucks to carry them to the adjacent Cambodian town of Poipet.
Some Cambodian workers said they would be back.
From June 1 to 17, more than 84,000 Cambodians crossed the border in Aranyaprathet to Cambodia.
Rayong's provincial governor ordered concerned parties to restore confidence among employers and foreign workers as the exodus of Cambodians had severe impacts on Thailand's local agriculture, tourism, restaurants and construction sectors. The governor also ordered the regulation of foreign workers in the eastern province.
Panitan Wattanayagorn, political science lecturer at Chulalongkorn University, said 3 million foreign workers had yet to be regulated and they included what he termed as 'the highly problematic' Rohingyas.
Regulation would provide workers from neighbouring countries with basic rights, protect them from human trafficking and improve Thailand's national image, he said.