A police informant will be called as a witness during a two-day court hearing for William Tyrrell's foster mother, who denies giving misleading or false information to the NSW Crime Commission.
The charges relate to evidence the 56-year-old gave during a hearing into William's disappearance from his foster grandmother's home.
William was last seen at the property at Kendall, on the NSW Mid-North Coast, in September 2014.
The foster mother, who cannot be identified, did not appear during a brief mention of her case at Sydney's Downing Centre Local Court.
Police Prosecutor Amin Assaad told the court it would be a "voluminous" matter.
"We anticipate calling one witness, that's the police informant," he said.
The hearing will involve about 500 pages of evidence and transcript from the Crime Commission, and possibly some audio recordings of the commission, the magistrate was told.
The woman's plea of not guilty was confirmed.
The NSW Crime Commission works alongside NSW Police and can hold hearings and supply evidence to courts to facilitate prosecutions.
The maximum sentence for misleading the body is five years imprisonment.
William's foster father, who also cannot be named, has pleaded not guilty to two charges of giving false or misleading evidence to the crime commission.
He will face a two-day hearing in October, where audio recordings of his police interview are expected to be played.
Nobody has ever been arrested or charged over three-year-old William's disappearance, despite a $1 million reward being offered and hundreds of persons of interest being interviewed.
There was a renewed police search around areas of interest in Kendall last year.
