An interim administrator has been appointed to oversee the estate of Virginia Giuffre after she died without a valid will, meaning multiple lawsuits that had been on hold can now resume.

Giuffre, 41, died on a small Western Australian farm, 80km north of Perth, in April.

On Monday, the Western Australia supreme court appointed lawyer Ian Torrington Blatchford to take interim control of her estate, thought to be worth millions.

The estate is likely to include what is left of a reported £12m out-of-court settlement Giuffre received in 2022 from Andrew Mountbatten-Windsor – formerly Prince Andrew – after she alleged he sexually abused her when she was 17. He has denied the allegations.

Blatchford’s A$400-an-hour appointment means legal proceedings stretching from Perth to New York can proceed.

There had previously been a bid by Giuffre’s sons, Christian and Noah, to be appointed administrators of the intestate estate.

But supreme court documents reveal Giuffre’s lawyer, Karrie Louden, and her housekeeper, Cheryl Myers, mounted a legal challenge to prevent the brothers from being granted authority over the estate.

Monday’s court orders note “the administrator is appointed as the legal representative of the deceased in any legal proceedings or arbitration in which the deceased was a party prior to her death”.

The fact Giuffre died without a valid will stalled a high-profile defamation case filed in October 2021 by Rina Oh – who at the time went by the name Rina Oh Amen.

Like Giuffre, Oh says she was abused by the late convicted sex offender Jeffrey Epstein.

She was suing Giuffre in a New York federal court for US$10m over her social media posts published in October 2020 and statements made in a memoir and a podcast, which Oh says wrongly portrayed her as an accomplice of Epstein, rather than one of his victims.

Oh claims the allegations against her caused “devastating” reputational harm and were repeated by international media.

The dispute played out in tit-for-tat lawsuits across state and federal New York courts.

This includes a December 2022 counteraction filed by Giuffre alleging that Oh played an abusive role within Epstein’s circle, cutting her during sadomasochistic encounters while Epstein watched, according to court documents. Oh strongly denies the allegations.

“I still suffer from post-traumatic stress disorder, especially when I am asked to provide more documents and go through the discovery materials and looking at the court documents. I get flashbacks,” Oh told the Guardian before Blatchford was appointed.

“We were waiting for the estate to be established. It has been six years, and I just want it over.”

In April this year, a New York appeals court ruled that Oh’s defamation claim could continue against Giuffre’s estate, as civil liabilities survive a defendant’s death.

Now that the interim administrator has been appointed, Oh’s legal team will be able to formally serve the estate and resume proceedings.

Blatchford declined to comment on the complex legal legacy he was appointed to manage.

Monday’s WA supreme court orders detail four “existing and other legal proceedings”.

The list includes a 2015 defamation lawsuit against Ghislaine Maxwell that was resolved in Giuffre’s favour and “an arbitration” involving US attorney Alan Dershowitz. Giuffre in 2022 dropped a defamation lawsuit against Dershowitz.

The WA court orders also state that “the administrator is authorised as the deceased’s legal personal representative to do all things necessary in the exercise of that power in respect of the deceased’s memoir titled Nobody’s Girl, which was co-written with the journalist Amy Wallace.

At the beginning of the book, Wallace shares details of Giuffre’s fraught final months, including multiple health problems.

Giuffre originally came to international prominence for the Mountbatten-Windsor case, which was filed in New York and under the Child Victims Act.

It alleged Epstein trafficked her at Ghislaine Maxwell’s London townhouse, Epstein’s New York mansion and on his private island.

In May this year, Sky Roberts, Giuffre’s father, claimed on Piers Morgan Uncensored that: “There’s no way that she committed suicide … somebody got to her.”

A WA police spokesperson said this week that Giuffre’s death was not being treated as suspicious.

“Major crime detectives are preparing a report for the coroner,” the spokesperson told the Guardian.

The WA coroner’s court could not provide a timeframe as to when investigations into the circumstances surrounding Giuffre’s death would be completed.