A NSW Supreme Court judge has supported the estranged daughter of television mogul Reg Grundy in her attempts to resolve a half-billion dollar difference in estimates of her late father's wealth.
Dr Grundy died at his Bermuda home in 2016, leaving a will that effectively bequeathed all his wealth to his second wife Joy, except for a lifetime annuity of $US250,000 to his daughter by his first marriage, who changed her name by deed poll to Viola La Valette.
Ms Grundy, who is also an executor of the will, and co-defendant companies in Ms La Valette's lawsuit challenging the will argue Dr Grundy's estate had a net value of around $214 million.
"They don't deny that it may have been a higher figure, but they contend that it is neither necessary nor appropriate to inquire further," Supreme Court Justice Geoff Lindsay says in a judgment released on Thursday.
Their figure is based on totalling legacies that would have occurred had Ms Grundy not survived him by 30 days.
"The artificiality of that process of reasoning is reinforced by information in the public domain (in particular, 'the BRW Rich List' published by Fairfax Media Limited) suggesting that in 2015 the deceased was possessed of wealth worth $809 million," the judge said.
The co-defendants argued that the value of the estate was irrelevant to the daughter's claim for "relief" as the fund available to her is larger than any legal entitlement.
In Dr Grundy's autobiography, cited in the judgment, he wrote that the "loss" of his daughter was the "greatest heartbreak" of his life.
The limited provision for her in the will "may reflect a perception on his part that she was unreliable in her handling of property and in need of protection," Justice Lindsay says.
But he says the extent and value of property owned by Dr Grundy when he died was controversial partly because his widow had made disclosures reluctantly when "confronted with facts" established by Ms La Valette.
Ms Grundy had also refused to give her a copy of her father's will.
Justice Lindsay says it was "not unreasonable" for Ms La Valette to establish the full extent of her father's estate, before final judgment is made on her claim.
Ms Grundy, as administrator of the estate, was "required to make disclosures about his property, and property transactions, outside NSW", even though the court's jurisdiction to make a family provision order in favour of Ms La Valette was limited to property in NSW.