Australia's richest person, Gina Rinehart, said her children are unsuitable to manage her multi-billion dollar trust.

Rinehart said her children are too spoiled, do not work, do not trust each other and lack requisite capacity or skill, [and] the knowledge, experience, judgment or responsible work ethic, according to court documents obtained by WAToday.

However, her three eldest children, Hope Rinehart Welker, Bianca Rinehart and John Langley Hancock, said their mother should be removed from her position of trustee. They claim she is deceitful with gross dishonesty.

Rinehart and her children reportedly engaged in a series of emails arguing with each other. That culminated in an ultimatum by Rinehart in which she allegedly said her children would go into financial ruin, warning them that could face a $142 million capital gains tax unless they allow her to control the trust.

It is of course not reasonable to think anyone would pay the CGT on your behalf, she wrote in an email according to WAToday.

Her children responded in court, saying their mother used the bankruptcy threat to force them to give up control of the trust.

Her conduct has been such that the plaintiffs have no confidence that there is any scope for improvement on this fundamental point, they said according to court documents.

The chief financial officer of Hancock Prospecting, implored her children to drop the suit by offering them quarterly payments from the trust. Court documents also show that the Nationals Senate Leader also emailed the Hope Welker, asking her to keep the suit out of the public eye.

Newspapers and lawyers get people to say nasty things, he said, according to WAToday. Before it really gets out of hand, I would try to get it back in house and out of public view.

The youngest daughter, Ginia, 25, stood by her mother saying that her siblings were not fit and proper persons to be trustees.

Ginia said her brother and sisters have a history of conflict with each other and their mother. She said that also did not have good relationships with the current executives with the trust and if her siblings took control of the trust, it would have dire consequences on the family's mining empire.