Former Guantanamo Bay detainee David Hicks will face media on Wednesday and outline his reasons for lodging an appeal against his conviction in the US for supporting terrorism.

Lawyers for Mr Hicks lodged the appeal papers in the US Court of Military Commission Review on Tuesday, Fairfax Media reported on Wednesday.

They are seeking a summary dismissal of the conviction because the offence was not a war crime at the time Mr Hicks was detained and his guilty plea was made under duress.

“A guilty plea induced by the unholy trinity of violence, threats and improper promises cannot be allowed to stand,” the appeal document said.

Hicks spent more than five years in Guantanamo Bay before being transferred to Adelaide’s Yatala Labour Prison in 2007 and was released in December that year.

The 37-year-old South Australian admitted providing material support to terrorists as part of a plea deal which facilitated his transfer to Australia.

Mr Hicks and his lawyer, Stephen Kenny, will hold a press conference in Sydney to explain the appeal.

“He (Hicks) will give a statement, and Stephen Kenny will give a statement explaining process, what steps need to go through,” a Justice Campaign spokeswoman told AAP.

She would not provide details about the statement, but said Hicks “obviously … would be talking about the appeal and what it means to him”.

A US court last year quashed a similar charge of material support for terrorism relating to Salim Hamdan, Osama bin Laden’s former driver.