Trevor Lankin, also known as Roy Lankin, was last seen in Mparntwe/Alice Springs in May 2004.

The then 25-year-old Indigenous man was reported missing after relatives became concerned for his welfare, when he failed to return home or make contact with family.

Police say he last accessed his bank account on May 18, 2004, the day after he was last seen.

More than two decades on, Mr Lankin's disappearance remains unresolved.

In recent weeks, community Facebook pages have been resharing Mr Lankin's photograph and missing person details to renew awareness and prompt fresh information, amid fears his case may have faded from public view.

At the time of his disappearance, police believed Mr Lankin may have travelled to the Papunya community after leaving Alice Springs.

Mr Lankin is around 185 centimetres tall, weighing about 75 kilograms, and of medium build.

He has a mole under his right eye and a missing front tooth.

Police say he has several distinctive scars, including an eight-centimetre scar on his inner left forearm, a five-centimetre scar on his upper left arm, a four-centimetre scar on his left forearm, and a three-centimetre scar on his abdomen.

Detective Senior Constable John Beer previously said police hoped the publication of Mr Lankin's image would trigger someone's memory.

"It is of major concern that Mr Lankin has not contacted his family, nor accessed his bank account," he said.

"Anyone who may have information — no matter how insignificant it may seem — is urged to come forward."

Anyone with information about Trevor Lankin's whereabouts is asked to contact police on (08) 8951 8888 or Crime Stoppers on 1800 333 000.