Unions targeted by the commission have been given just more than a week to produce thousands of pages of financial, contractual and personnel documents stretching back seven years. They have been warned that failure to produce documents could lead to up to six months jail.

Insiders agree the commission's official written request for documents has the potential to entangle Mr Shorten, renowned as a hands-on factional player in the ALP. The request for documents includes a period when Mr Shorten was an Australian Workers Union leader.

Most of the five unions targeted by the commission into union governance, slush funds and corruption, have extensive links to Mr Shorten and his dominant right-wing faction, including the AWU, the Transport Workers Union, the Health Services Union and Communications, Electrical, Plumbing Union.

His personal power base includes the AWU and the plumbers' division the CEPU. Political allies of Mr Shorten now control the Victorian branch of the scandal-prone HSU after a bitter and expensive election in 2012.

The bank-rolling of the Shorten-linked HSU team in both the 2012 and 2009 union elections by other unions and union-linked slush funds, looms as a key point of interest for the royal commission.

So, too, have the unions been asked for details about donations

to other unions or political parties, and any money or benefit received from companies with whom unions have negotiated.

AWU insiders fear that on financial dealings with companies, Mr Shorten may face a grilling over contributions to the AWU from construction companies during construction of the Eastlink tollway through the mid-2000s.

The commission's request for documents to both the HSU and AWU ask about specific slush funds, notably the AWU-linked Industry 2020, revealed by Fairfax Media in 2012. The fund generated more than $500,000 from employers, other unions and law firms between 2008 and 2013. It was run as a sub-factional slush fund by sole director Cesar Melhem, a loyal Shorten lieutenant and his Victorian AWU successor.

Mr Shorten attended at least two Industry 2020 fundraisers. Money from the fund was used to bankroll HSU election campaigns by the Shorten-aligned Diana Asmar in 2009 and 2012.

Copies of the requests for documents by the royal commission, obtained by Fairfax Media, ask for seven years of detailed financial records for each branch of the respective union in each state.

One senior union official described the demands as ''impossible'' to meet. Multiple union sources believe the process has set the unions up to fail due to the breadth of the commission's demands and short time-frames for providing information.

Before last year's federal election the Coalition promised a judicial inquiry into the 20-year-old corruption scandal at the AWU that involved Julia Gillard doing legal work for her then boyfriend, AWU official Bruce Wilson. But the scope of the inquiry was dramatically widened into a royal commission after extensive reports in Fairfax Media.

A key commission focus are slush funds including the TWU's McLean Forum and the left-wing Construction, Forestry, Mining and Energy Union, whose Victorian construction division was fined $1.25 million this week for criminal contempt of court. A spokesman for Mr Shorten said unions should co-operate with the royal commission.