About 600 workers demanded the government to end what they call unfair employment conditions and promote job security during a rally to mark World Day for Decent Work on Saturday.
The rally along Ratchadamnoen Avenue in Bangkok was joined by members of the Thai Labour Solidarity Confederation (TLSC), the State Enterprises Workers' Relations Confederation (SERC) and the International Labour Organisation Convention Mobility Network.
TLSC leader Sawit Kaewwan said during the gathering that labour groups are urging the government, including Labour Minister Phiphat Ratchakitprakarn, to scrap short-term employment or labour contracts in both the public and private sectors.
The groups also demanded the government scrap any plan to privatise state enterprises dealing with energy, transport, banking and telecommunication.
Mr Sawit said the government must operate state enterprises to keep public utility prices low, which reduces production costs and household expenses.
He suggested the government consider the State Enterprise Development Bill by the SERC to understand how to shape up state enterprises instead of privatising them.
Somporn Kwannet, a TLSC adviser, said more firms are hiring contract workers. However, the contract doesn't guarantee full benefits and job stability.
Osot Suwansawet, president of the Government Employee Union of Thailand, said he is a public health contract worker at Maharaj Hospital in Nakhon Si Thammarat.
He said that even though he earns minimum wage and is a Social Security Fund subscriber, he has no access to pensions or layoff compensation.
The Ministry of Public Health, for example, hires over 200,000 contract workers in public hospitals across the country. However, welfare benefits, which labour advocates have demanded for over 20 years, are not forthcoming from their employers.
Tang, 23, a contract worker at a factory in Chon Buri, said he earns about 18,000 baht a month while permanent staff in the same position are paid over 30,000 baht each, which is unfair.
"The company pays an annual bonus to permanent workers worth over 10,000 baht each. [Contract workers] also contribute to the company's profits but we are not eligible to receive benefits equally."