The Coronal Investigation on the Disappearance of William Tyrrell proposed

William Tyrrell vanished from a home in Kendall, NSW in 2014.

The case of the missing child of NSW, William Tyrrell, must be turned over to the examining magistrate and an investigation has been proposed for next year.

On the fourth anniversary of William's disappearance, police in New South Wales announced that investigators had been talking to the coroner and an investigation before it was proposed to NSW Deputy Chief Colonel Harriet Grahame.

In a statement, police in New South Wales said investigators in the case "would like to acknowledge the continued strength and courage of William Tyrrell's families today.

"Over the past year, researchers continued to explore research lines in an effort to find out what happened to William, including a large-scale forensic search," he said.

AAP

The deputy coroner requested a summary of the evidence, according to the statement, which will be delivered before the end of the year.

The investigation will be "an opportunity to test the information and evidence gathered by Strike Force Rosann and promote the investigation."

"This is another step to ensure that the answers are provided to William's loved ones," the statement said.

William was playing in his grandmother's yard in Kendall on the north coast of NSW when he disappeared on September 12, 2014.

He was three years old.

Despite a large-scale search, no trace of it has been found.