The Catholic Archbishop of Adelaide will plead not guilty to a charge of concealing child sexual abuse.

Archbishop Philip Wilson, 64, has been charged with one count of concealing information about a serious indictable offence, namely the 1971 sex assault of a 10-year-old boy by former priest James Patrick Fletcher in Maitland in the NSW Hunter region.

Wilson was excused from appearing on Thursday at Newcastle Local Court.

But his lawyer Simon Buchen said his client would formally enter a plea of not guilty.

The matter returns to court on June 17.