BHP Billiton and a security firm that guards major government buildings are among hundreds of Australian names linked to a Panama law firm that helps the rich hide money.

The ABC’s Four Corners program revealed the links involving the mining giant and Wilson Security as part of an investigation into a massive leak of 11.5 million documents from Mossack Fonseca.

A Gold Coast businessman and a Hong Kong billionaire who is one of Australia’s biggest foreign investors and whose company is the majority shareholder in SA Power Networks, are also identified.

Tax authorities are investigating 800 Australian clients of Mossack Fonseca, which helps heads of state, criminals and celebrities set up companies in offshore tax havens.

Australian Taxation Office deputy commissioner Michael Cranston said at least 120 are associated with an offshore service provider for Mossack Fonseca in Hong Kong.

Four Corners claimed that BHP used Mossack Fonseca offices in the British Virgin Islands to register five companies linked to its aluminium, diamonds, steel and finance arms.

Millions of dollars in loans were moved through the tax haven from London. BHP said it did not use the companies to avoid tax and each one paid tax in Britain.

The documents also show that Wilson Security, which guards the ATO, Defence Department and detention centres, was helped by Mossack Fonseca to hide links between its holding company and Hong King billionaire brothers Raymond and Thomas Kwok.

The pair were original directors of the British Virgin Islands-based holding company and charged as part of a major bribery case in Hong Kong in 2012.

Four Corners claims that within a week of the charges, the brothers resigned.

But two new companies set up by them then appeared as directors, with Mossack Fonseca having helped the brothers hide their identities.

Wilson insists the brothers are not involved in the company.

Internal Mossack Fonseca emails also show that an infrastructure company that owns electricity assets in South Australia used the law firm to set up subsidiaries in Panama and the British Virgin Islands.

Two companies related to the infrastructure firm CKI Holdings, which is owned by Hong Kong billionaire Li Ka-Shing, were taken to court by the ATO in an attempt to reclaim $400 million in back taxes.

The case was settled in 2015 for less than one tenth of the amount, Four Corners said. CKI insists all its companies comply with tax rules.

CKI Holdings is the majority shareholder in SA Power Networks, which runs South Australia’s electricity infrastructure.

Gold Coast businessman Ian Taylor is also claimed to “rent” his name to companies wanting him to pretend to be a director of offshore firms set up by Mossack Fonseca.

He told the ABC while he had acted as a nominee director and shareholder for hundreds of offshore firms, his passport and identity had been stolen and used to forge directorships.

The leaked documents date back four decades and were initially given to a German newspaper which shared the data with the International Consortium of Investigative Journalists and 100 major media outlets including the ABC.

More than 214,000 offshore entities connected to people in more than 200 countries are included in the data, along with information about how banks helped create 15,000 companies in tax havens.

Mossack Fonseca director Ramon Fonseca told Reuters that the “vast majority” of the companies his firm set up were used for “legitimate purposes”.

– with AAP