Thousands of children working in Indonesia's tobacco fields are being poisoned by handling the leaves of the toxic plant, an international investigation has found.

Key points: Children on tobacco farms showing symptoms of nicotine poisoning including vomiting, dizziness

Children on tobacco farms showing symptoms of nicotine poisoning including vomiting, dizziness Tobacco companies buying leaves not ensuring product is safely produced

Tobacco companies buying leaves not ensuring product is safely produced Call to have working with tobacco classified suitable only for adults

The Human Rights Watch report said child labourers were not being properly protected when handling the leaves from the plant, and that the tobacco companies who bought the leaves were not ensuring that the product was safely produced.

Human Rights Watch is calling to have working with tobacco be classified as a hazardous occupation that is suitable only for adults.

Indonesia has half a million tobacco farms in Indonesia, mostly on the fertile plains of Central and East Java.

The plots are mostly family-owned, and children help their parents in the fields in what can be hazardous work.

Human Rights Watch spoke to 130 young workers over two seasons.

One 12-year-old told them that after she went to her family's tobacco crop field to water the plants, she felt nauseous from the smell of the tobacco.

"Then I vomited in the fields and my dad told me to go home to rest," she said.

The reports author, Margaret Wurth, said they found the children were being exposed to nicotine, toxic pesticides and other dangers when working on tobacco farms.

"About half the children we interviewed reported at least one specific symptom consistent with acute nicotine poisoning," she said.

"Nausea, vomiting, headaches and dizziness and this can happen when children, when workers are handling tobacco and it can actually be absorbed through the skin.

"The long term affects on children are unknown."

Families don't realise the danger

Ms Wurth said most of the children they interviewed worked on their own family's farms or neighbours and extended family members farms.

"And in many of these communities it is common for children to start helping on the farm from a young age — the children want to help support their families, help their families with their livelihoods," she said.

"The problem is this is hazardous work and the families we interviewed, no one has ever given them good information about what the dangers of exposure to nicotine and toxic pesticides can be for children.

"So they don't realise just how dangerous this work could be for the children in the long term."

There are not many ways of making money in the fields of central Java and Ms Wurth said they understood tobacco farming was an important livelihood for many farmers in Indonesia.

"There are more than half a million tobacco farmers here, we just want to make sure children aren't doing hazardous work on these farms, producing this kind of tobacco that is then bought by some of the biggest companies in Indonesia and the world," she said.

"I saw small children working, surrounded by big piles of tobacco leaves and the smell was overwhelming, [they] talked about the residue it left on their hands and how sick it made them feel.

"This is toxic work that children shouldn't be doing."