After toiling in the sun on an Israeli farm for 17 hours, Praiwan Seesukha, a 37-year-old Thai migrant worker, went to sleep next to other exhausted labourers in a crowded shed. He did not wake up.

Israeli authorities failed to investigate Praiwan’s death and speculation is mounting among rights groups that poor working conditions on Israel’s farms could be behind the death of migrant workers like him.

About 25,000 Thai nationals work in Israel, mostly farming vegetables, fruit and seeds, according to a Human Rights Watch (HRW) report published on Wednesday.

An estimated 122 Thai migrant farm workers have died in the country since 2008, including 43 from a heart condition known as sudden nocturnal death syndrome, according to Israeli newspaper Haaretz. The cause of death of 22 migrants is unknown because, as in Praiwan’s case, the authorities failed to investigate.

The report, based on interviews with 173 Thai workers in farms across Israel and produced in partnership with Israeli rights watchdog Kav LaOved – Worker’s Hotline, calls on the Israeli government to enforce its own labour laws, which set a minimum wage and limit the amount of hours a person can work.

“The success of Israel’s agricultural industry depends to a large extent on the labour of Thai migrant workers, but Israel is doing far too little to uphold their rights and protect them from exploitation,” said Sarah Leah Whitson, Middle East and north Africa director at HRW.

Israel exported $0.9bn of agricultural goods to the EU in 2012 (pdf), according to the government’s statistics office.

Whitson said: “Israeli authorities need to be much more active in enforcing the law on working hours and conditions, and in clamping down on employers who abuse workers’ rights.”

Israel restricted the number of Palestinians who could work in the country in 1993, which left an employment hole for private companies. In response, an agreement between Israel and Thailand was signed in 2012, paving the way for a stream of migrant workers from south-east Asia to travel to Israel. The workers hoped to send money to their families back home.

Thai workers on a farm at the Israeli-Gaza border. Photograph: Ilia Yefimovich/Getty Images

The migrants, who mostly come from Thaliand’s north-western provinces, are paid “significantly” below Israel’s minimum wage and work up to 17 hours every day, according to the report.

Labourers told HRW that they “felt like dead meat” after milking cows and harvesting avocados from 4:30am to 7pm. They said their employers treated them “like slaves”, using binoculars to spy on them while they were working.

“Workers at several farms complained of headaches, respiratory problems and other maladies, including burning sensations in their eyes that they attributed to spraying pesticides without adequate protection,” the report said, adding that many of the migrants struggle to access medical care or change employers.

Thai workers are promised the opportunity to change employers in Israel if they encounter any problems. One Thai migrant worker told HRW that he tried to change employers because hot weather and dust were giving him respiratory problems. More than a year later, his request still had not been answered.

Israel’s population, immigration and border authority and its economy ministry are responsible for enforcing labour rights in the country’s agricultural sector. Both declined to comment on HRW’s report, the organisation said.

• This article was corrected on 21 January 2015 to clarify that Israel has not banned Palestinians from working in the country, but has restricted the number it allows to be employed.