The fleeing migrants -- who work inb menial jobs but often lack official work permits -- have returned home en masse after Thailand's military regime warned last week that illegal foreign workers face arrest and deportation.
The junta has since insisted there is no "crackdown" and blamed false rumours for the exodus of what could be, by some estimates, the entire undocumented Cambodian population in Thailand.
"We need to work closely together to allay fear among the Cambodian labourers in Thailand," said Cambodian ambassador Eat Sophea on Tuesday, adding it was not the policy of the current administration "to crack down on labourers regardless of their (legal) status".
After talks with the Thai foreign ministry permanent secretary Sihasak Phuangketkeow in Bangkok, she also dismissed rumours of the shooting and abuse of Cambodian migrants by Thai authorities -- among the factors believed to be triggering the exodus.
"The reports about shootings, the reports about other abuses are rumours and are not true, it's been taken out of context. We agreed to work together in order to clarify any issues," Eat said.
- 'Scared of being arrested' -
The two countries have also agreed to set up a hotline on labour issues.
"We agreed to set up some form of a hotline... to communicate requests for clarification for assistance to facilitate those labourers who wish to return to Cambodia," the Cambodian ambassador said.
At the main border crossing between the two countries in Poipet -- a bustling town home to several large businesses, casinos and hotels -- a few hundred Cambodian migrants arrived in Thai military trucks and police cars on Tuesday morning.
"The number of Cambodians returning from Thailand into Poipet in just over a week reached 157,000 by this morning," said Kor Sam Saroeut, governor of the northwestern province of Banteay Meanchey where the checkpoint is based.
Around 20,000 others have crossed the border at O'Smach, a checkpoint some 250 kilometres (155 miles) northeast of Poipet, according to the governor and a senior Cambodian police official.
Bun Veasna -- who was employed as a construction and seafood worker in Chonburi province just east of Bangkok -- was escorted into Poipet by Thai police along with his brother on Tuesday.
The 32-year-old said he decided to come home after hearing that the Thai army would arrest all illegal Cambodian migrants, and that some had even been killed by the military.
"All the Cambodians in my area have returned home. We were scared of being arrested and jailed or killed there. We did not feel safe," he said.
Thailand's military regime has strongly denied it has been forcing Cambodian labourers out of the country and dismissed reports of killings as "groundless rumours".
Last Wednesday it had threatened to arrest and deport all illegal foreign workers, but the foreign ministry has since stressed the "great importance" of the role which migrant workers play in Thailand's economy.
In the past Thai authorities have turned a blind eye to illegal labourers because they were needed when the economy was booming.
But now the country is on the verge of recession after the economy contracted 2.1 percent quarter-on-quarter in the first three months of 2014.
The International Organisation for Migration has previously estimated that around 180,000 undocumented Cambodian workers live in Thailand. It is unclear exactly how many now remain in the country.