The 70-year-old, who calls himself "Little Pebble" and claims to communicate with Jesus Christ and the Virgin Mary through visions, was on Thursday placed on a new supervision order that allows him to return to "holy land" he owns north of Nowra.

A petition opposing Costellia-Kamm's return appeared online four days later and has since amassed more than 700 signatures.

The petition, titled "Deny this man access to the Shoalhaven!!!", is authored by a Joshua Murphy and calls on local state and federal MPs to "act immediately to prevent this man returning to our area".

"While many years have passed, it is blatantly clear to the public that William Kamm (Little Pebble) should not be allowed to return to the Shoalhaven. His hideous crimes should result in justice, that means he can not come near the area he perpetrated in. This is not only for the victims but also for our area," the petition reads.

Member for Gilmore Fiona Phillips told ACM she had written to the Attorney-General, the Premier and the corrections minister, opposing Costellia-Kamm's return.

"Obviously we do not want William Kamm anywhere near back in the Shoalhaven. William Kamm has caused so much harm, so much hurt in this community and it would absolutely be an injustice and terrible for him to return to our community."

"I was a young person then when Little Pebble was around and I know that it impacted so many people. There's no way that he should be allowed to return."

Read more: Mystery Koonawarra backyard fire causes mega smoke plume

Asked whether it was possible to prohibit Costellia-Kamm from the region in light of the court's ruling, Ms Phillips said: "I think the Attorney-General has the power to do that and I think they should act".

Member for the South Coast Shelley Hancock has vowed to write to the NSW Attorney General "seeking his intervention in this disgraceful decision".

"William Kamm should not be able to return to the Shoalhaven under any circumstance!" she wrote online on Tuesday.

"There was a reason he was placed on an extended supervision order and additional interim supervision orders when he was released from prison.

"The harm he has caused many in our community is simply unacceptable and I am extremely disappointed in the Supreme Court's decision."

Costellia-Kamm was released to parole in 2014 after being convicted of sexual and indecent assaults committed against two children in his cult in the 1990s.

He had claimed to have received doctrine that he was to be the last pope and was to "re-populate a royal dynasty" after the second coming with 12 "queens" and 72 "princesses".

His lawyers told the court he wished to lead a "rather quiet" life on the cult's grounds, avoiding the expense of renting in Sydney.

Concern was raised about his relationship with a young woman, who left her home in New Zealand in November 2019 to join the cult soon after she turned 18.

But there was no evidence Costellia-Kamm, who the court heard has a narcissistic personality disorder and is still highly regarded in his community, had been in contact with the woman when she was underage.

The judge said conditions of the supervision order needed to manage the risk of further serious sex offending.

Under the supervision regime, Costellia-Kamm will not be allowed to sign any new leases for residences at Cambewarra without the approval of a government supervisor.

He will also have to provide that supervisor any necessary keys and access codes to allow access to Cambewarra for monitoring purposes.

- with AAP