Hundreds of people have gathered in the remote Western Australian town of Carnarvon to mark a horrific chapter in the state's history, with the hope it will lead to healing.

Readers are warned that images of Indigenous people who have died appear below.

Under the blazing sun, they watched as Carnarvon elder Bob Dorey, shirtless and painted, performed a traditional dance to release the souls of 200 Aboriginal men, women and children who never made it back home from the lock hospital prisons.

Bob Dorey and Kathleen Musulin have been pushing to find out the true history of the islands for several years. ( ABC North West: Karen Michelmore )

"It's been a few years, I think, but a lot of hard work and sometimes tears, but it's finally come to this now, this day," said Mr Dorey, a Malgana elder.

"We are pretty proud of our crew."

Mr Dorey has been working with Kathleen Musulin, whose great-grandmother was taken to the islands, and academics and researchers who have helped bring the story to light.

It was hidden for generations because of the shame, and pain, it engendered.

Between 1908 and 1919, hundreds of Aboriginal people were rounded up by police, many placed in chains, marched to Carnarvon and shipped to the islands.

These days it is a two-and-a-half hour boat ride, but 100 years ago it was far more arduous and took up to a week.

Lock hospitals backed by WA laws

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 51 seconds 1 m 51 s Ugly past of 'lock hospitals' slowly revealed (Photo: Battye Library)

The reason for their detention was that police suspected them of having venereal diseases.

It was government policy and facilitated by the Aboriginal Act of 1905.

The facilities on the islands were inadequate, there was no contact with their families back home, and they underwent experimental medical treatments.

Government reports showed that in one year, a quarter of all the Aboriginal deaths in WA occurred on the islands, researchers said.

Descendants of those held on the islands have been pushing for acknowledgement of the history for years.

Between 1908 and1919, hundreds of Aboriginal people were removed from their homelands and placed on Dorre and Bernier Islands, 50km from Carnarvon in WA. ( ABC North West: Karen Michelmore )

Sorry, this audio has expired 100 years since Indigenous people last placed in "lock hospitals"

"It's been a very emotional journey," said Kathleen Musulin, whose great grandmother was buried on the island.

"There were times I would become so emotional — I would cry and I didn't understand why I was experiencing that.

"I spoke to a couple of elders and I said to them 'why am I so emotional about this, why am I crying?' This never happened to me, this happened to the ancestors.

"What they said to me was because they weren't acknowledged, and they've been forgotten about, I'm carrying their pain.

"I think that a lot of us today, we carry the pain from our old people from the past and what happened to them."

The WA Government and the Shire of Carnarvon have acknowledged the history, with the Government in the process of building a permanent memorial statue on the cliffs looking out to the islands.

"We accept that this was a really horrific piece of Western Australian history," Regional Development Minister Alannah MacTiernan said.

"There's justice in just the truth being brought out and being acknowledged."

Descendants retrace steps

The barren and remote Dorre and Bernier Islands were a 50km journey by boat from the WA mainland. ( ABC North West: Karen Michelmore )

This week descendants returned to Dorre Island with some of the academics and researchers who reveal the story.

Concrete slabs, rubble and traces of corrugated iron from which Aboriginal people built shelters dot the sparse island.

Richard Weston, CEO of the indigenous body the Healing Foundation, said the visit to the island, along with the ceremony, marked the start of a healing process.

"Healing does start with truth-telling," he said.

"The truth of the lock hospital story is not a pleasant one, it's very confronting, it's painful — it's traumatic and there is still much hurt that is carried within our communities.

"But this isn't a story that only happens in Carnarvon, it's a common theme around the nation."

Lock hospitals also existed in Port Hedland, in WA, and later in Barambah and Fantome Island in Queensland.

There were also leprosy field hospitals in WA, the Northern Territory, and Queensland.