But Bianca Rinehart has in turn been accused of making false claims in her sworn affidavit to the court, with counsel for Gina Rinehart asserting that she misled the court regarding what she was told about the family's mining interests.

The claims and counter claims emerged on Monday as Bianca Rinehart gave evidence in the ongoing, bitter court battle between the two warring sides of the Rinehart family.

Ms Rinehart and her brother, John Hancock, claim that their mother has defrauded them of billions of dollars in mining profits and are demanding that she repay them money they claim is rightfully theirs.

They want the deeds and agreements which provide the basis for the distributions of the profits to be set aside.

But Mrs Rinehart is attempting to cut her children's court action off at the knees, seeking an order from the court that John Hancock and Bianca Rinehart be forced to deal with the matter through arbitration and that their application be dismissed or permanently stayed.

Crucial to this question is whether the deeds and agreements signed by the estranged Rinehart children were properly entered into or whether, as they claim, they were made under duress and without the benefit of crucial information that was deliberately withheld.

On Monday, counsel for Bianca Rinehart, Christopher Withers, said that in August 2006 his client had effectively been forced to sign the so called 'Porteous Deed' - an agreement regarding her grandfather's second wife Rose Porteous .

"Your honour will see from Bianca Rinehart's evidence that she felt threatened and isolated," Mr Withers said.

"She was distressed and crying in Hancock Prospecting's offices. We say that the inequality of bargaining power was palpable."

"This is a young woman who was compelled by her mother and Hancock Prospecting to sign a deed against her will."

Later, Bianca Rinehart told the Federal Court her personal email account had been hacked.

Ms Rinehart said her emails had been "compromised". "Recently all of my emails have been deleted, which I didn't do," Ms Rinehart said.

"It's not hard to imagine who might have done that ... in whose interests that would have been."

However, counsel representing Mrs Rinehart, Bruce McClintock, SC, accused Bianca Rinehart of falsely claiming that her mother had deliberately withheld an agreement between creditors of the lucrative Hope Downs Deed.

Mr McClintock produced about 10 emails which were sent to the "Hope Downs Team", of which Ms Rinehart was a member while employed by Hancock Prospecting, which contained drafts of the agreement.

"You want her honour to think that you were completely ignorant of these matters," Mr McClintock said.

"I would have had a summarised understanding," Ms Rinehart replied.

"Where in your affidavit does it say that you had a summarised understanding?" Mr McClintock continued.

"Well, it doesn't," Ms Rinehart replied.

She later admitted that she had leaked documents relating to the Hope Downs Trust to her siblings while working for Hancock Prospecting.

"I didn't think I was doing anything wrong and I still don't," she said.

The hearing continues.