Mining magnate Gina Rinehart told children to go find jobs if they were unhappy with fortune

Mrs Rinehart has tried various legal avenues to keep details of the dispute quiet but lost what may be a final effort in the country's High Court.

In an email that emerged on Friday, Mrs Rinehart warned two of her daughters they were risking the lives of their families by taking legal action against her.

"You know I have done everything reasonably possible (and then some!) to keep you out of the media during your childhood and life given my love for you and concern for your safety and have been very largely successful," she told one of her daughters, Hope Welker.

"Any prolonging of this unnecessary and irresponsible action and "fishing trip" and lawyer feast will cause continuing media attention and greater jeopardy for the safety of you and your children and family."

Only one child, Ginia Rinehart, has taken her mother's side – and she has been rewarded with appointments to the boards of three companies. She accused her siblings of being "motivated entirely by greed".

In a biting response, her brother, John Langley Hancock, said he supported his family through share trading while his mother's new favourite drove a $AUS1.2 million car.

"I'd love to have inherited projects and royalties to work with – instead I've got to rely on the skills I possess," he said. "I won't be able to replicate Ginia earning the achievement of a Rolls-Royce at 25, but at 36 I'm now turning my set of skills towards helping several very interesting projects achieve commercialisation."

Mrs Rinehart was this week ranked 29th on the Forbes rich list.