The Australian Taxation Office has been refused access to court documents in the multibillion-dollar trust fund battle between Australia's richest person, Gina Rinehart, and her children.

The tax office in Western Australia applied in the NSW Supreme Court in November to view several documents, including tax advice given by accounting firm PricewaterhouseCoopers in relation to the bitter family battle.

Bianca Rinehart, Gina Rinehart and Ginia Rinehart.

But the ATO repeatedly failed to be represented in court and didn't specify the documents it wished to view from the court file, which is more than 30 large folders, Justice Paul Brereton said in a judgment handed down on Monday.

Two of Ms Rinehart's children, John Hancock and Bianca Rinehart, allege their mother acted "deceitfully" and with "gross dishonesty" in her dealings with the trust, set up in 1988 by her father, Lang Hancock, with her children as the beneficiaries.