The Fair Work Ombudsman on Monday revealed it has begun a national review of the 417 visa, which many young people use to work on holidays for up to two years. Ombudsman Natalie James said the review would examine "anomalies" in the system in specific regions where lots of workers take temporary jobs.

It is estimated there are more than one million foreigners with work rights — or 10 per cent of the national workforce — on temporary visas.

FWO Ombudsman, Natalie James said trends showed the number of overseas workers could rise to between 2.5 million and 3.5 million over the next five years, with an expected increase in vulnerable workers seeking help for job issues.

According to the FWO media statement, among the issues the review will focus on were collecting government data to investigate businesses "most commonly" helping workers get the second-year extension, and talking directly to employees.

According to the report, in the past two financial years, the FWO has received about 2000 requests for help from workers on the 417 visas, or one-third of all requests from visa holders.

Those requests show a rising level of underpayment in sectors including hospitality, agriculture and accommodation industries.

The FWO recouped some $67,000 in underpaid entitlements for 77,000 417 visa-holders in 2011-12, rising each year to $345,000 for 309,000 417 visa holders last fiscal year.

Ms James said the review would also go on in parallel to some 51 court actions the FWO has been involved in since July 2009, about 20% of the ombudsman's entire legal activity in the past four years.

"Restaurants account for the highest number of litigations involving overseas workers, with 10 matters placed before the courts, followed by retail (6), fast food (4) and cleaning and maritime (3 each)," she said in a statement.

"The 51 litigations related to alleged underpayment of overseas workers totalling more than $3.8 million and included 10 cases involving 417 visa-holders."

The best defence for an overseas worker against being underpaid or treated unfairly is to know their rights. They have the same workplace rights as any other worker in Australia. Information to assist both employers and employees from culturally and linguistically diverse backgrounds has been translated into 26 languages on the Fair Work Ombudsman website at www.fairwork.gov.au. Overseas workers, or employers, seeking advice can also call 13 13 94. The Fair Work Ombudsman has fact sheets tailored to overseas workers and international students on its website.

Follow this link for the full FWO media statement: http://www.fairwork.gov.au/about-us/news-and-media-releases/2014-media-releases/august-2014/20140804-working-holiday-entitlements-review