Since arriving in Singapore for work last August, welder S. Kumar has not sent a single cent home.

The 42-year-old was looking forward to supporting his wife and two young children back in India, but his hopes were dashed when his first pay cheque arrived.

He received just $200, less than half of the $530 monthly salary he was promised. The reduced sum is just enough to support himself.

His supervisors had different explanations for the disparity each month: The company was withholding part of his salary for safekeeping; it was for the dormitory; electricity bills had to be paid.

Mr Kumar said he was not informed of any extra expenses before he arrived here. He was also promised overtime pay, but does not receive it despite working 11-hour days.

"I came to Singapore thinking I could finally start a new life for my family," he said in Tamil. "But I haven't sent any money home."

Mr Kumar claimed he is not the only foreign worker in his company whose wages have fallen so far short of what was promised. It is the same for more than 60 of his colleagues. "But we don't want to create problems. We came so far, we have so much to pay back," said Mr Kumar, who had paid his agent $2,800 to come to Singapore.

He would have stayed silent. But last month, he was sent for surgery to treat a gastrointestinal perforation that was causing severe abdominal pains. His firm was not keen on paying for the follow-up checks and medication, he said.

After his supervisors told him this month that they planned to send him back to India to recuperate, Mr Kumar sought help from the Humanitarian Organisation for Migration Economics (Home).

"My company told me, 'You're too expensive. Go back to India. Get well, and come back.'I told them that I'm not well yet. And I was scared that if they sent me to India, they wouldn't bring me back again. I didn't make money. I lost it. How can I go home?"

Mr Kumar is just one of the victims of what Home has termed "wage theft". These workers find themselves receiving less than their legally or contractually promised wages.

Mr Sohag Fazlul Haque from Bangladesh was told he would be paid $20 a day, but learnt he would receive $17 daily instead upon reaching Singapore. He was not paid extra for overtime, and got 1.5 times his daily rate - instead of double the daily rate that he was entitled to - on Sundays.

His company, Glaziers Engineering, told him in December 2015 that he owed the company money for various reasons, from $950 for his levy, to $50 for office utility bills. This was deducted from his monthly salary in instalments.

"I say, like that, how to makan (eat)? Boss say, 'All men the same pay'," recalled Mr Sohag, 30. "He says, 'You don't like, you go home'."

Last February, his company informed him that it would deduct his entire salary to repay his outstanding loan. He was forced to borrow from friends for food that month.

In May, Mr Sohag hurt his back carrying a heavy glass panel meant to be handled by three men. His supervisor had set just two men on the job. Mr Sohag filed a work injury compensation claim and was awarded about $8,000. He suffered 5 per cent permanent incapacity of his back.

"Very hard work here. Heart pain, body pain," said Mr Sohag, who flies home to Bangladesh tomorrow. "That's why I don't want to come back to Singapore."