Thousands of garment workers have returned to work in Cambodia since a strike for higher pay was put down with deadly force by the authorities last week.
However, employers are now filing cases in courts against trade unions over the two-week dispute.
Khieu Sambo, an attorney representing the firms against the six unions involved in the strike, told Reuters news agency that more than 150 factories had filed cases and more were being prepared.
"The lawsuits will focus on incitement to strike, damage to property and assets, coercion and threatening workers who want to work," Ken Loo, secretary-general of the Garment Manufacturers Association in Cambodia (GMAC), said on Friday.
Chea Mony, president of the Free Trade Union, one of those targeted, said the judiciary was politicised but he would still fight the charges in court.
"They sued us because they want to intimidate us so we won't strike any more and we won't help the workers. We are not afraid."
The garment-makers' association said most workers had returned to work around the country by Friday.
However, only about 60 percent had shown up at the Canadia Industrial Park in the capital, Phnom Penh.
The park is home to factories that make clothes for Western brands such as Adidas AG, H&M Hennes & Mauritz AB and Puma SE.
The UN human rights agency said this week five people were killed and 20 wounded by gunfire and beatings on January 3 when military police opened fire on the workers, who were demanding a rise in minimum pay to $160 per month from $100.
The government had offered first $95, then $100, a rise of 25 percent.
The unions rejected that but GMAC's Ken Loo said a minimum wage of $100 would come into force on February 1.