Gina Rinehart's legal team has criticised a "surprise" suggestion that the multi-billion dollar trust at the centre of her family's long-running dispute be wound up.
In yet another twist in the case between the mining magnate and two of her children, John Hancock and Bianca Rinehart, the latters' barrister Christopher Withers raised concerns on Friday as to what would happen if the Supreme Court cannot reach a decision on who will be the new trustee.
So far every proposal for a replacement trustee - including Bianca Rinehart, Mr Hancock and independent trustees - has been criticised by one or more parties during the lengthy court proceedings.
The longer the case "drags on, the more disputes there are" between Mr Hancock and Bianca Rinehart and their mother, Mr Withers argued.
He said the court may need to "face up to the fact that the only option is to wind the trust up".
This would also act to appease any concerns over what would happen to a lucrative joint venture between Hancock Prospecting (HPPL) and mining giant Rio Tinto if a trustee outside the Rinehart family was appointed to take over the running of the $5 billion trust, he said.
"If the trust is wound up and my clients and other trustees become shareholders in Hancock Prospecting then this risk would go away."
But Gina Rinehart's barrister Bruce McClintock SC said an application to wind up the trust had nothing to do with the proceedings before the court and came as "something of a surprise".
"I see no power to wind up the trust ... your honour would not be entertaining it," he told Justice Paul Brereton.
The latest turn comes more than two years after Mr Hancock and Bianca Rinehart lodged a claim against their mining magnate mother.
The pair allege Gina Hancock acted "deceitfully" and with "gross dishonesty" in her dealings with the trust, set up in 1988 by her father, Lang Hancock, with her four children as the beneficiaries.
The pair were previously supported by their sister Hope Welker, but she withdrew from the case last year.
Ms Rinehart, who is supported by her youngest daughter Ginia, has denied the claims but agreed to bow out as trustee last year.
Justice Brereton dismissed the newest proposal on Friday saying that he would not regard an application to wind up the trust as being within the scope of the present case.