An acrimonious sibling dispute over a million dollar waterfront property has led to a High Court judgement overturning their late father's will.

It's becoming increasingly common for courts to overturn wills, says one top lawyer.

The Grace Avenue property. Picture: Supplied.

Maureen Parsons, 68, and Stephen White, 64, won a High Court battle against their sister Jocelyn Chambers, 66, over a beachfront Mt Manganui home which had been left to them by their late father Royce White.

The three children were beneficiaries of their parent's trust which owned the $1.7m property in Grace Ave, a block away from the Mount.

When Royce White, a retired Te Kuiti farmer, died in 2012, he wanted his children to continue to own the land, which had been in the family since the 1920s.

But that 'laudable intention' led to four years of court battles, and the withering away of their inheritance through costly legal bills.

According to the judgment, the two lawyers who administered the trust had the property valued at $945,000 in 2013, and offered the property to Jocelyn Chambers.

But White and Parsons didn't want the sale to go ahead, believing the valuation was too low, and wanted the property sold on the open market and the proceeds split evenly. It was valued again in March 2016 at $1.725m.

Court proceedings were launched in 2014 by White and Parsons to remove the trustees and the case was heard over a four day trial at the High Court at Hamilton in April.

Justice Heath said the house should not be sold to Chambers, and instead, should be sold to one of the siblings at the 2016 valuation, or sold on the open market.

The judge said the litigation had "exacerbated an already strained relationship".

Outside court, Jocelyn, who owns a Te Kuiti farm with her husband Gerald, said she had taken care of her father towards the end of his life.

"The sibling wanted to overturn my father's wishes. There began a battle for four years basically. They've been rewarded for it. I was dragged into it. I got completely and utterly over-ridden. It's a pretty sore point for me."

But White, an Auckland real estate agent, said the judgement "fully supported our stance".

He issued a joint statement with Maureen Parsons, saying: "Our families have endured both financial and emotional stress over the past 4 years which could and should have been avoided."

Their father's main request was that everyone was to be treated equally, he said.

He said the litigation had cost the family in excess of $300,000.

White said when he tried to enter the property to inspect his late father's chattels, he set off an alarm and the police were called. He said the property was rented out at $50 to their father's caregiver for four years against his wishes.

Auckland lawyer Bruce Dell, whose firm has handled in excess of 25,000 wills, said it was "lunacy" that judges were effectively rewriting people's wills.

He compared it to another case involving Deborah Chambers' court dispute over her late husband Sir Robert Chambers' will with one of his sons.

"You've got highly intelligent people with mixed families, children on each side, they make a will and one of the kids comes along and wants to change it. It's just lunacy."

Chambers is also involved in a high-stakes litigation in the United States over a multi-million dollar Facebook stock scam.

With her husband Gerald, and their son Julian they are suing more than a dozen defendants including rabbis, lawyers, and the congregation of a Brooklyn synagogue, for more than $30 million plus legal expenses in the New York Supreme Court.

They were tricked into investing around $9m in non-existent Facebook stocks before the social media giant listed on the New York Stock Exchange in 2012.

Bevan Hurley/Stuff.co.nz