Another of Prime Minister Malcolm Turnbull's investments is under scrutiny, with revelations he has a financial stake in the global parent company of the scandal-plagued 7-Eleven empire.
Fairfax Media can reveal Mr Turnbull has shares in two international investment funds that invest in Japanese conglomerate Seven & I Holdings.
Seven & I's major subsidiary is Seven-Eleven Japan, which is the parent company of 7-Eleven in the United States. The US company in turn licences the billionaire Withers and Barlow family, who own Australia's scandal-plagued stores.
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More questions than answers at 7-Eleven inquiry
7-Eleven staff claims panel member Dr David Cousins faces a grilling from the Senate inquiry into wage fraud.
As a Senate committee prepares to probe the wages exploitation scandal on Friday, Labor has claimed the investment raises concerns Mr Turnbull must address.
"He has not uttered a single word of support for these workers and people have been legitimately asking why?" said Lisa Chesters, the chair of Labor's Fair Work Caucus Committee.
A landmark investigation by Fairfax Media and the ABC last August found workers, most of them international students, were being massively underpaid and payrolls were being doctored. The revelations triggered a series of corporate resignations and ongoing investigations.
The Turnbulls typically limit their investments to offshore managed funds where they have no control or influence over investment decisions. But Mr Turnbull has in the past disposed of investments deemed politically or morally difficult.
In April last year he divested his shares in a fund that was investing in tobacco company Philip Morris International after coming under media scrutiny. He also instructed his investment adviser not to invest in any funds with an exposure to tobacco in the future.
Unlike many politicians, Mr Turnbull chooses not to invest through a blind trust, giving him a greater level of scrutiny over his own investments.
Mr Turnbull updated his publicly-available register of pecuniary interests in March 2014 to declare he had purchased shares in iShares MSCI Japan ETF, which invests 1.19 per cent of its USD $18 billion in Seven & I. He updated it again in June 2015 to declare he had purchased shares in Deutsche X-trackers MSCI Japan Hedged Equity ETF, which invests 1.19 per cent of its USD $1 billion money into Seven & I.
The Prime Minister's Office has declined to comment on these investments.
Law firm Maurice Blackburn wrote to Mr Turnbull in September urging him to offer an amnesty to workers who breached their visa conditions because of 7-Eleven's exploitation but the firm's principal Josh Bornstein says the response was inadequate.
"We got a letter back months later saying go and talk to someone else," Mr Bornstein said.
"It's the largest wage fraud case we've seen - possibly ever but certainly for a very long time - and I don't recall him saying anything about it at all."
Opposition Leader Bill Shorten also wrote to Mr Turnbull about the scandal in September, pushing for an amnesty.
"I welcome the opportunity to work with you on this matter to ensure a fair outcome for 7-Eleven workers," Mr Shorten wrote.
But Mr Shorten's office says Mr Turnbull did not respond.
Immigration department officials have said exploited workers have not and will not have their visas cancelled.
A Senate hearing will probe the scandal in Canberra on Friday, with 7-Eleven's co-owner Russ Withers, new chairman Michael Smith and interim CEO Bob Bailey set to give evidence. The investigation into working visas will also hear from Fair Work Ombudsman Natalie James and David Cousins from the Fels Wage Fairness Panel.
Former ACCC chief Allan Fels is running a compensation scheme for workers who believe they have been ripped off.
7-Eleven this week announced it had appointed a former police officer to investigate internal criminal activity.
Mr Smith, who replaced Mr Withers in October, said the company was making significant progress towards "satisfactory remediation and prevention" of wage abuse.
"What has occurred is unacceptable and abhorrent and we are building capability internally and utilising external expertise to rectify the impacts of what has occurred and prevent them from happening again," he said.
The first Australian 7-Eleven opened in Melbourne in 1977. The company now has 620 stores across the country, generating sales of approximately $3.6 billion a year.