Thailand's government has drawn criticism for its plan to use prisoner labor from more than 40 labor and human rights groups.

The government plan aims to curb human trafficking caused by a labor shortage in the fishing industry. Thailand's record in fighting human trafficking was downgraded to its lowest level in 2014 by the U.S. Department of State.

The plan announced last December would allow ex-prisoners and consenting prisoners with less than a year left in their sentence to work in the industry. Currently, more than 170 prisoners work on fishing boats. Much of the product is shipped to U.S. and Europe.

In a letter to Thai Prime Minister Prayuth Chan-ocha, 43 labor and human rights organizations criticized the government's plan, saying the project "poses a serious threat to the human rights of prisoners."

"The project will also likely fail to address the fundamental causes of the labour shortage that fuels trafficking in Thailand's fishing industry," the letter said. "If implemented, this initiative could strengthen arguments that the Thai government is unwilling to take serious steps to address human trafficking on fishing boats."

Thailand's fishing industry employs about 300,000 people, 90 percent of whom are migrant laborers.

The majority of migrant labor currently comes from Myanmar and Cambodia.

Organizations such as Trades Union Congress and Human Rights Watch were named in the letter.

"Thailand has repeatedly said that it's committed to end forced labor and human trafficking, but this pilot project heads in precisely the opposite direction and will make things worse," Phil Robertson, deputy Asia director of Human Rights Watch, said. "This prisoners on fishing boats project should be immediately scrapped."