Prosecutors could appeal after a Newcastle District Court judge quashed the conviction of Adelaide's former archbishop Philip Wilson on charges of covering-up clergy sexual abuse.

Wilson had been serving a minimum of six months home detention.  He was the highest-ranking Roman Catholic official in the world to be convicted of concealing the sexual abuse of minors by priests. 

He had been convicted in Newcastle Local Court of covering up the crimes of paedophile priest Jim Fletcher in the Hunter Valley dating back to the 1970s.  One of the victims, Peter Creigh, told Wilson of the abuse in 1976; but Wilson failed to bring it up to police when they finally arrested Fletcher in 2004.

Despite this, Newcastle District Court Judge Roy Ellis praised Wilson as a "clearly an intelligent and articulate witness" and that "there were very honest features of his evidence to provide a strong platform for him to be an honest witness".

That prompted another survivor of clergy sexual abuse in the gallery to stand up and shout, "Bullshit, that is a disgrace!"

Ellis was similarly heckled last week when he gave permission for Wilson to attend the hearings via video link so he could avoid the media; that is how Wilson attended Thursday's court hearing.

The Catholic Archdiocese of Adelaide welcomed the ruling and said in a state, "We now need to consider the ramifications of this outcome."