Many migrants working as waiters, gardeners and cleaners in Thailand's booming tourism sector face pay below minimum wage, discrimination and no paid leave, according to an investigation of labour abuses in the country.
More than 30 million tourists are expected to visit Thailand's palm-fringed islands, white beaches, temples and vibrant nightlife this year, and the thriving sector accounts for some 10% of national gross domestic product.
However, a report on Wednesday by Swedish groups Schyst Resande and Fair Action found evidence that many migrant workers from Thailand's poorer neighbour Myanmar are being exploited in the southern resorts of Khao Lak and Phuket, at hotels used by three of Sweden's top tour operators.
In all, 29 migrants were interviewed for the report, 18 of them working mainly as cleaners, gardeners and waiters in seven hotels used by REWE Group's Apollo, TUI Group's Fritidsresor and Thomas Cook Group's Ving.
The others were employed by companies supplying the hotels with services and goods including a bakery and laundry company.
"Among those we interviewed, it seems worse for those that work at the suppliers. They have longer working days, they have less vacation and they also face a lot of discrimination," said Fair Action project manager Amanda Söderlund.
In a joint statement, Ving, Fritidsresor and Apollo said violations of national and international laws could mean the termination of a contract with a hotel.
"There are few companies and organisations that can control all supply chains in all countries of the world," the statement said. "Ving, Fritidsresor and Apollo are together working with thousands of hotels worldwide, it is difficult for us to follow up on all these individual hotels."
The operators said that was why they were working with Travelife, a certification scheme for hotels focused on environmental standards and fair working conditions.
Thailand under scrutiny
Almost two-thirds of the migrants in Fair Action's report said they were paid less than the country's daily minimum wage of 300 baht, with a far higher proportion among migrants employed by hotel suppliers.
Three laundry staff said they worked up to 19 hours a day during the peak tourism season with only two days off a month. Another reported working 16-hour shifts with no time off.
Several workers described not being paid for taking time off to treat burns and other injuries sustained in the work place.
Thai workers, by contrast, received higher salaries and better benefits, including better accommodation, longer holidays and maternity and sick leave, the report said.
Ms Söderlund said concerns about "illegally low wages" paid to migrant workers were raised with the same tour operators in a 2012 Fair Action investigation, but little action had been taken.
"We think that the tour operators should step up and take responsibility. They have known there are issues for several years. They can make an impact if they take their responsibility seriously," Ms Söderlund told the Thomson Reuters Foundation.
The operators said only one fifth of the Swedes visiting Thailand travelled with them. "It takes more than three tour operators to make sustainable change occur," they said.
Thailand has come under increasing scrutiny over its treatment of migrants following allegations of human trafficking, abuse and exploitation in the fishing industry and more recently, the processing of chicken for export.
It is one of the region's biggest importers of migrant labour, yet regulations are enforced loosely and many workers face exploitation and ill-treatment.
Employers frequently confiscate identification documents to keep unregistered workers from running off and to maintain pay rates below the national minimum wage.
Last year, the US State Department downgraded Thailand to its Tier 3 list of worst offenders in an annual ranking of nations by their efforts to combat human trafficking.