Orchid farmers petitioned National Legislative Assembly (NLA) chairman Pornpetch Wichitcholchai Wednesday to delay enforcing the executive decree on foreign workers.
In explaining the move they said their businesses may fold under the harsher punishments intended to prevent human trafficking.
The farmers' call comes as the government reforms the law to better monitor the workforce and tackle the country's human trafficking situation, which has put Thailand in the Tier 2 Watchlist of the US Trafficking in Persons (TIP) report.
Orchid farmers, who generally hire a large number of foreign workers, are the first group to complain over potentially dim future prospects, fearing they will not be able to fully comply with the new law.
The farmers are further worried about other financial problems, especially high fines imposed on violators.
- See main story: Worker shortage looms
With fines ranging from 400,000-800,000 baht for wrongdoings committed for each worker, Mit Pancharoen, chairman of the orchid farming cooperative, said Wednesday he feels the farmers are being treated like "criminals".
The illicit actions include failure to hire workers registered with the government.
In the past, mistakes were based on each violation, which could encompass multiple foreign workers.
Mr Mit said 75% of farmhands are foreigners, so if orchid farmers cannot follow the new law they will face huge financial difficulties.
He said it is also unclear whether the new law requires public companies to also seek permission to hire foreign workers.
Cooperative representatives, who gathered at the NLA Wednesday, called on lawmakers to ask state agencies overseeing the new law, which was announced on June 23, to delay its enforcement.
The new decree, which involves fees and high fines, also raises fears that some state officials may use it as a means to protect vested interests, said Mr Mit.
He urged the government to carefully listen to farmers' concerns before enforcing the law.
The law will increase costs both above-board and "under the table," said deputy Democrat leader Sathit Pitutecha, referring to the fees which employers pay for labour registration procedures and potential bribes given to officials.
He said the financial impact could be heavy as Thailand is struggling with an economic slowdown, adding the law will cause some businesses to fear hiring foreigners.
But inspector-general for labour Ananchai Uthaiphtthanachip said Thailand needs stricter laws to better protect foreign labourers and cope with human-trafficking gangs.
"We don't have any intention of prohibiting employers from using foreign workers," he said.
"But they must brought over legally."
Many employers have opted not to register their foreign workers, pushing the government to ramp up the penalties, said Mr Ananchai.
In terms of registration fees, he said they are considered a necessary cost employers have to shoulder for hiring inexpensive workers abroad, adding they would "ensure fair business competition" in the matter.
