The list of bizarre conditions Olivia had to stick to for her $25 million inheritance.

The “secret daughter” of a Perth billionaire is being challenged by her father’s estate after she was awarded $25 million back in 2015.

Olivia Mead, the 21-year-old daughter of businessman Michael Wright, initially inherited $3 million after her father’s 2012 death. In 2015, a Supreme Court ruling found Ms Mead should receive an inheritance of $25 million after she argued it would not cover “proper maintenance support, education or advancement in life”.

However, the estate is arguing Ms Mead had “come to court with a quite extraordinary” list of items in 2015, including Pilates lessons until she is 97 and the purchase of 20 pairs of $300 shoes each year, ABC News reports.

The list also included a crystal-studded Kuhn-Bosendorfer piano worth around $1 million, $40,000 for holidays every year and a guitar worth $250,000.

Ms Mead’s father Michael was the son of mining magnate Peter Wright, who was Lang Hancock’s business partner. He was 74 when he passed.

But in drawing up what later become a hotly-contested will, Mr Wright’s $3 million trust fund for the daughter not many knew about came with stringent conditions.

Not only did Ms Mead have to wait until she was 30 to access the money, but she couldn’t convert to Buddhism, Islam, be convicted for drink driving or possession of marijuana.

In an interview with Sunday Night back in 2015 after the initial Supreme Court ruling, Ms Mead’s mother Liz Mead, who had a short, two-year relationship with Mr Wright prior to her daughter’s birth, said the conditions were as if he were “ruling from the grave”.

“I was shocked. I didn’t think he would do that,” she said.

"Michael would love the fact that he can control everything. So, if he was sitting here, he would say it's character-building. And he fully expected Olivia to fight for anything that she was going to get. And he would be quite proud of the fact that she has."

His daughter, however, couldn't understand the logic.

"For a long time I thought... that maybe he didn't love me.

"He was a strange man. To be honest, I can't tell you why he would do that," she told the program.

During the court hearing, the estate's lawyer acknowledged Ms Mead deserved more than a "bread and butter" lifestyle, but that $3 million should be more than sufficient.

At this stage, as the case continues, the outstanding $22 million is being held from the 21-year-old until it's all resolved.