Omar Khadr is refusing to attend his military commission hearing in Guantanamo Bay, saying authorities are trying to "humiliate" him.

Khadr is objecting to having to wear black-out goggles and earmuffs for a ride in a windowless van from his cells to the courtroom.

The judge has urged Khadr's lawyers to talk to him, and warned he could be brought to court by force in order to be advised of his right to attend the hearings.

Khadr is accused of killing an American soldier and other terror-related crimes when he was 15 in July 2002

The pretrial hearings are to determine whether self-incriminating statements he gave can be used as evidence.

The defence maintains the statements were given under torture or abuse; the prosecution denies any mistreatment.