Over 85,000 children have worked in dangerous conditions, according to the Labour Ministry, as a researcher said another group of children is being told to leave school to help provide for their families.
Pannee Sriyudhsak, the head of the ministry's Department of Labour Protection and Welfare, said a 2015 survey carried out with the National Statistical Office showed 85,806 out of 10,876,275 children aged between 5 and 17 have worked in hazardous conditions.
Of those working in dangerous conditions, 65,601 were aged 15 to 17; 14,093 were between 13 to 14; and 6,112 were between 5 and 12, according to the survey.
A total of 692,819 children aged between 5 and 17 worked in safe environments and worked no more than 48 hours a week. About half of them worked in the agricultural sector, 19% in trade, 12% in restaurants, and the rest in other sectors, said Ms Pannee.
Sinee Chuangchum, from Khon Kaen University's Research and Development Institute, said one group of children is in a grey area where they are quitting school to become breadwinners.
She cited a community where she found an 11-year-old child from a poor family who was forced to drop out of school to sell garlands, take care of his two younger brothers and do household chores.
Some children needed to get up around 3am to help their parents slaughter chickens for sale, she said, adding they worked in hazardous conditions as they had to handle dangerous tools.
She said some parents thought urging their children to work would bestow the children with patience and self-discipline.
But any form of work that is physically, socially or morally dangerous and harmful to children and which interferes with a child's ability to attend school is considered child labour in the international arena, said Ms Sinee.
Child labour is a challenging problem that requires multi-disciplinary approaches, she added.
She urged the government to step up efforts to provide humanitarian assistance to children who are at risk of being exploited, saying law enforcement alone won't solve the problem, especially if the government wants to meet its ambitious target to end child labour in dangerous working conditions by 2020.
Child labour laws have been strictly enforced, she said, adding employers who were found to allow children to work in unsafe conditions will face harsh repercussions.
The department also produced a handbook on the labour rights of migrant workers in the country, she said, adding the handbook is available in Thai, English, Lao, Cambodian, Burmese and Vietnamese.