When David Hicks arrived at Guantanamo Bay 13 years ago, he had a gash to his head and the goggles he had been forced to wear were so full of sweat it was like pouring out a glass of water, former guard Brandon Neely says.

These two guys in this picture with me are my friends and they where tortured by the United States #TortureReport pic.twitter.com/pkGHFogioV — Brandon Neely (@BrandonTXNeely) December 11, 2014

"He didn't speak that day; he looked really tired and walked really slow," Mr Neely told Fairfax Media in an exclusive interview.

"I saw David Hicks on January 11, 2002, and I escorted him off the bus at Camp X-Ray through in-processing, then into his cell on Bravo block."

Mr Neely had arrived only a few days before the first detainees so he could get acquainted with the centre.

Mr Neely said he would never forget his first impression of the cage structures he thought looked like "dog kennels".

He has since left his position as a guard and has spent the past few years campaigning to have Guantanamo Bay closed, while also reaching out to former detainees he met there.

"Honestly, I am not surprised but very ashamed it [Guantanamo Bay] is still open. I hate knowing I took part in something so horrible."

Mr Neely was happy at the news that Mr Hicks was to be cleared on the charge of supporting terrorism.

"They told me David was a trained killer, would kill me in a heart beat. Now, they are telling the world he is innocent," he said.

"For 13 years, they lied about David to the world and everyone that stepped foot on Guantanamo. Glad to see them have to admit they where wrong.

"I truly hope that David may be able to have some sort of closure and start his healing process. I just want David to be happy."

Mr Hicks who says he still suffers the after-effects from his incarceration is also "disturbed" that the detention centre is still open.

"When [US President Barack] Obama entered office and signed a decree to promise to close Guantanamo ... I was filled with hope, believing common decency and the law would prevail," Mr Hicks said.

"After personally being there for 5½ years, being subjected to torture, isolation, medically experimented upon, incommunicado etc, I was left broken destroyed, suicidal.

"Nothing has changed ... imagine how the men still there after all these years are coping, how destroyed they must be," he told Fairfax Media.

Mr Hicks was one of two Australians held there.

Mamdouh Habib was sent to Guantanamo after being the subject of an "extraordinary rendition" to Egypt where he was held in secret and tortured.

Mr Habib was released in 2005 without any charge being laid against him. He has since settled a law suit against the Australian government about his treatment, for an undisclosed sum.

The detention centre still holds 127 men who have not been charged or faced trial.

Among them is Hambali one of the men alleged to have been involved in the 2002 Bali bombings.

He has been held since 2006 as a so-called high-value detainee, But he has not been charged with any crime.