EXCLUSIVE
Sunny Liu is the embodiment of one of Australia's biggest problems. The young Chinese student is one of hundreds of thousands of temporary foreign workers illegally exploited and underpaid in what has become a widespread "black economy" for jobs.
When Michael Smith took over on Wednesday as the new chairman of convenience store chain 7-Eleven, he said the underpayments in his humiliated company was just the tip of the iceberg, part of a "very widespread problem".
Now for the first time, a Fairfax Media investigation can outline the extent of it - hundreds of thousands of workers across the economy, in food courts, cafes, factories, building sites, farms, hairdressers and retail - being exploited on low wages and believing they have no power to ask for their rights.
The comprehensive study in conjunction with Monash University* has revealed  80 per cent of foreign language advertisements offering wages below legal rates. Many of them are openly advertised as "black jobs". 
Ms Liu was paid $8 an hour to work at a restaurant in suburban Melbourne and $12 an hour at another job in the food court at Southland shopping centre.
"I feel in the workforce I am [treated] somehow inferior to other local Australians," said Ms Liu, a student at Monash University, who came to Australia from China last year.
"Even though I do have the legal student visa, I am entitled to some working rights. I was not treated as if I have those working rights."
Little research or official data exists on how many temporary foreign workers and students are employed in Australia, let alone how many are being illegally underpaid, but the Fairfax investigation surveyed Mandarin-language websites, where it was common for jobs to be openly advertised at $10 to $13 an hour, significantly below Australia's legal minimum wage of $17.29 an hour.
The  study of 1071 job advertisements aimed at temporary foreign workers, largely from China, Malaysia, Hong Kong and Taiwan, show the vast majority offer work either below the minimum wage or the award.
Ms Liu found her work at the restaurant through website yeeyi.com, where all the job advertisements are in Mandarin.
She knew she was being underpaid - her wage after two weeks was lifted from $8 to $10 an hour - but feared losing her job if she spoke out.
"I didn't dare to speak up at the time as I had just got to Australia, as I didn't know what the situation was with employers," she said.
Some of the Chinese language advertisements openly admit they are offering "black" work which, signifies it is an illegal job.
Illegal underpayment is not confined to particular industries, and is evident across a wide range of low skilled or semi-skilled jobs.
If the results were replicated across the variety of Australian visas used by students and temporary foreign workers, it's likely many hundreds of thousands of people are being illegally underpaid at any one time.
At the extreme end, the investigation uncovered workers paid as little as $4 an hour, and shady networks of middle-men who demand extra payments from prospective foreign job seekers to secure work.
Fairfax Media has spoken to one job-seeker, who does not want to be identified, but who said he received death threats from a middle-man.
The labour hire middle-men often take a cut from three sources: the workers themselves, employers who hire the workers, and from owners of cheap hotels who house them.
In Mildura, one middle-man who hired out workers to local farmers also owned a caravan park, where he housed four workers per tiny room.
The National Union of Workers (NUW) has called for urgent action on the labour hire middle-men at the centre of many of the employment scams.
"If you sell alcohol in Victoria you need a licence , if you want to trade people you need nothing," said Tim Kennedy, the union's national secretary.
"Labour hire is completely unregulated, all you need is a phone and a spreadsheet to be a labour hire provider."
At the end of last year, there were more than 750,000 foreigners in Australia with temporary work rights, mostly on student, working holiday and 457 visas. Another 470,000 people were here on visitor visas, largely for tourism.
The number of temporary visa holders has more than doubled since 2000 and has risen sharply from negligible levels in the mid 1990s.
This is a starkly different labour market from that which greeted the surge of migrant workers after World War II. Back then, newcomers typically had permanent residency and far greater legal and work rights than today's foreign workers on visas.
In the modern era, some visas require the worker to retain the support of the employer to stay in Australia and also include, in the cases of student visas, restrictions on hours a week worked.
The abuses were graphically highlighted by the recent Fairfax Media/ABC investigation into rorts at the 7/Eleven chain as well as an earlier ABC 4 Corners program that focused on the agriculture sector.
On taking over the company, Mr Smith said in a candid interview that he believed 7-Eleven was the tip of the iceberg.
"We have a problem in this country ... This has opened my eyes, I think we're at the beginning of the revelation of something that is a very wide-spread problem. I think in this country we will find very large numbers of young and foreign workers who are not paid properly."
The latest investigation, published today, indicates he is right, and that sectors of the Australian economy are increasingly reliant on illegal underpayment.
One Mandarin-speaking middle-man from Malaysia, who recruits farm workers, openly admitted the work was "black" labour, which in the Chinese community means illegal.
When asked if he minded other job-seekers being told this, he said: "It is no problem to admit it. I don't want the job seekers [to] misunderstand the position."
Other advertised jobs demand workers pay $3.30 an hour from their wages, or several hundred dollars in up-front payments.
In some cases workers accused the advertisers and middlemen of promoting scams and fake jobs to steal from them.
Poor English skills, a lack of local knowledge, and a fear that speaking out would result in them being forced out of Australia, contributed to the problem, foreign workers say.
Labor elder statesman, and its former national president, Greg Sword,  said employers needed to be made responsible for the underpayment of workers through the use of middle-men.
"There also needs to be legislative change so that employers cannot avoid their responsibilities ??? even though the middle-man may be paying workers $10 an hour, if it's exposed, the employer should be held responsible."
The results of the Fairfax investigation showing 80 per cent of jobs were illegally under-paid are likely conservative.
The investigation was based largely on an analysis of websites http://www.backpackers.com.tw/ , yeeyi.com and some foreign language Facebook pages. Most of the jobs appeared temporary or casual and did not include penalties and loadings.
It did not count jobs where no pay rates were disclosed. If such jobs jobs were included in the results it is likely the level of underpayment would be even higher.
Ms Liu, a journalism student who helped with the Fairfax investigation, said most of her friends from Taiwan and China were paid illegally, at rates below the legal minimum wage.
Some of Ms Liu's friends earn as little as $6 an hour working at Chadstone Shopping Centre. "It was quite a contrast when I went from English teacher in China to a restaurant waitress in Australia and the waitress job was paid much lower than the English speaking job."
bschneiders@theage.com.au ??rmillar@fairfaxmedia.com.au
* Additional research and reporting by Monash University journalism students Yanzhu Xu, Luke Mortimer, Ivy Yuan and Sunny Liu.