Ex-detective Gary Jubelin could become William Tyrrell 'scapegoat', says lawyer

A former NSW senior detective could become a scapegoat for the failed investigation into toddler William Tyrrell's disappearance if criminal charges against him are heard in a closed court, his lawyer says.

Gary Kevin Jubelin's barrister Margaret Cunneen SC has argued against an application by the NSW Police Commissioner to suppress certain investigation details and close the court hearing charges against her client.

Jubelin, 57, has pleaded not guilty to illegally recording four conversations in 2017 and 2018 as he investigated how three-year-old William went missing from a home in Kendall in September 2014.

In Sydney's Downing Centre Local Court on Tuesday, Ms Cunneen said her client had every reason to expect his case would be heard in open court so the evidence against him and his response is publicly known.

She referred to an affidavit submitted by Robin Bhatta for the commissioner which she said indicated the orders sought would lead to the public being misled.

"It would make the allegations against Mr Jubelin seem so much worse," Ms Cunneen said.

"The consequences of the orders ... is that it will always be intimated Mr Jubelin's alleged offences were the reasons, or the principal reasons, for the failure of this investigation.

"We submit he would be set up as a scapegoat for that failure."

Magistrate Ross Hudson will rule on the application later on Tuesday.