Immigration detention furore court-bound

A man who claims to be an indigenous Australian remains in an immigration detention centre east of Perth despite his lawyer's call for his immediate release.

George Newhouse, who represented Vivian Solon and Cornelia Rau, said his client Eddie David, 39, was born on Murray Island in the Torres Strait and is an Australian citizen.

He said Mr David had been detained at the Yongah Hill immigration detention centre since Friday after attending Centrelink.

"I've been told it's not the first time," Mr Newhouse told AAP.

"You have a vulnerable indigenous Australian man seeking support from the government and finds himself being arrested.

"I'm extremely concerned. It's a scandalous situation.

"It's hard to believe this could occur in Australia in the 21st century."

The Refugee Rights Action Network claims the Department of Immigration and Border Protection believes Mr David is an Indian, but a spokeswoman said he is a Fijian national.

"As part of the investigation, the department used fingerprint analysis and facial recognition comparisons," she said.

"The department also contacted the local Aboriginal council, who did not affirm his claims to be Aboriginal."

Mr Newhouse pledged to take the matter to the High Court if his client wasn't released by Tuesday evening.

While the spokeswoman said the department is fully satisfied Mr David is an unlawful non-citizen, she said the matter is subject to an ongoing investigation.