SYDNEY – Australia’s richest person Gina Rinehart has offered to end a messy legal battle with two of her children for control of a multi-billion dollar family trust by appointing a co-trustee, reports said Monday.

Two of Rinehart’s four children— John Hancock and Bianca Rinehart— are embroiled in a court case against their mother to have her removed as trustee of the trust which was established by their grandfather.

Gina Rinehart’s barrister David Russell told the Supreme Court on Monday that the mining mogul had written a letter to the two children in hopes of ending the long-running litigation, the Australian Broadcasting Corporation said.

Russell said the open letter states that “the first defendant would be willing to appoint a co-trustee” to the family trust.

New South Wales Supreme Court Justice Patricia Bergin said the offer was a “very big step” by Rinehart, whom business magazine BRW estimated in May to be worth $22.02 billion (US$19.5 billion).

But her son seemed wary.

“If only it were that simple,” Hancock told The Sydney Morning Herald.

The protracted row stems from a family trust set up by Gina Rinehart’s father, the late Lang Hancock, in 1988 with his four grandchildren as the beneficiaries.

Gina Rinehart was to run the trust, which holds a 23.4 percent slice of her company Hancock Prospecting, until the youngest grandchild turned 25 in 2011.

But just days before this date she sought to delay the payout until 2068 saying it would avoid a huge tax bill, prompting Hancock and sisters Bianca Rinehart and Hope Rinehart Welker to take court action.

Hope Welker has since pulled out of the legal battle, but not before documents submitted to the court exposed the bitter battle within the family, including John Hancock’s reported request for a $15 million “sorry payment” “direct from GHR (Gina Hope Rinehart) for how she treated me over these last 15 years”.

Ginia Rinehart— the sole sibling to remain loyal to their mother— has spoken out against her brother and sisters, saying: “This case is motivated entirely by greed and I have no doubt that one day soon my brother and sisters will regret putting money before family.”