The former president of a labour union for a factory in Ayutthaya is urging the government to speed up ratifying two International Labour Organisation (ILO) conventions.
Prawit Phohom, 55, said the conventions were vital to help reinforce the rights of labour groups.
Mr Prawit said he and his colleagues were treated unfairly by their employer who forced them to leave their jobs because they gathered as a labour group to negotiate conditions in 1996.
"We have the right to assemble as a group to negotiate with our boss," said Mr Prawit, who worked for a rubber factory. "We have the right to protect our interests when dealing with our employer. We did not hurt the factory. We did not hurt the employer." He is demanding the government ratify two ILO conventions aimed at strengthening labour groups and their bargaining power with employers.
ILO Convention 87 grants labourers the right to form groups without the need for state permission and prevents the government from interfering with their domestic and international activities.
ILO Convention 98 allows workers to collectively negotiate with employers and protects employees against unfair treatment and dismissal resulting from involvement in negotiations.
The conventions were also part of demands which labour networks including the Employee Council of Thailand, the Thai Labour Solidarity Committee and the State Enterprises Workers' Relations Confederation submitted to the prime minister on Labour Day on Sunday.
Mr Prawit started working at the rubber factory in 1995. He and his colleagues set up a labour union to protect the workers and negotiate an agreement with their boss regarding benefits and occupational health and safety improvements.
"We handled chemicals and heat while working in the factory. We stood a real risk of being involved in an accident at work," he recalled.
The factory management opposed their idea of setting up a union, resulting in a conflict between the workers and the employer.
In 2005, the company asked a labour court to dissolve the factory's labour committee.
In August 2006, the court ruled in favour of the workers, saying the employer did not have the right to abolish the labour committee.
The employer appealed to the Supreme Court in December 2007. In 2012, the Supreme Court upheld the lower court's decision. In the same month, members of the labour committee including Mr Prawit were allowed to return to the factory after having been suspended.
"But we were told there were no vacancies for us. We were asked to sit in a small room in the factory," Mr Prawit said.
Mr Prawit now sells flowers for a living near an industrial estate.