A group of foreign workers has successfully fought to claim back hundreds of thousands of dollars after they were drastically underpaid by their employer.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 2 minutes 45 seconds 2 m 45 s Foreign workers awarded 440,000 in backpay ( Michael Edwards ) Download 5 MB

The Filipino and Chinese nationals were employed in construction jobs in regional New South Wales by a Taiwanese company, Chia Tung.

Despite being promised almost $30 an hour, they said they were paid as little as $4 an hour and were forced to live in substandard accommodation.

The construction union said this case was one among many of companies exploiting immigration laws to exploit foreign labour.

One of the workers at Chia Tung was Filipino national Edwin De Castro, 43, an experienced construction worker who, like many of his compatriots, has been employed all over the world.

"I worked before in United Arab Emirates, followed by Japan in 1986, followed in 1988 until 2011 in North Africa, Algeria and from 2011 to 2013 in Singapore, and then December 2014 here in Australia," he said.

Mr De Castro arrived in Australia last year with high hopes.

He accepted a job with Taiwanese company Chia Tung, working on a construction project in Narrabri, a town north-west of Sydney.

Entering the country on a 457 visa, Mr De Castro looked forward to getting paid about $27 an hour, most of which he would send back to the Philippines.

But he said it turned out to be the worst experience of his time overseas.

"We are underpaid working with them. We are expecting to receive $27 per hour a week but what we received is only $7 or $10 per hour," he said.

"The working condition and also the accommodation, we are staying on the site. We are six persons in one bedroom.

"The other is staying on a shipping container while they are deducting $250 a week per person for our accommodation."

'This is a growing phenomenon'

After several months, Mr De Castro and the foreign workers were sacked.

They said they were thrown out of their accommodation in the middle of the night.

In all, 41 Filipino and Chinese workers on three separate projects were affected.

The construction union then stepped in and took the case to the Fair Work Ombudsman.

Now, the Ombudsman has ordered Chia Tung to back pay the workers $440,000.

Dave Noonan, the national secretary of the Construction Division of the Construction, Forestry, Mining and Energy Union (CFMEU), said: "This is a situation where workers on 457 and other temporary visa workers have been grossly exploited by the contractor.

"I think lots of companies are getting away with ripping off workers on temporary visas. This is a growing phenomenon and sadly we will see more of it."

Mr Noonan said the problem would only get worse when a series of Free Trade Agreements with Australia's major Asian trading partners — including China — came into place.

"With the Free Trade Agreements, which the Abbott Government is currently signing with countries like Korea and currently negotiating with China, these agreements are being kept secret," he said.

"But judging by the text of the Korean agreement, there won't be a requirement on companies to labour market test and look for local workers before they go overseas."