A Kendall resident has told the inquest into William Tyrrell's disappearance that he saw the boy being driven away in a car at high speed moments after the toddler vanished from the suburb on New South Wales' mid-north coast almost five years ago.

Key points: Retiree Ronald Chapman told the inquest he saw a young boy in the back of a fawn-coloured four-wheel drive

Retiree Ronald Chapman told the inquest he saw a young boy in the back of a fawn-coloured four-wheel drive He said he was wearing a Spiderman suit and had his hands to the window

He said he was wearing a Spiderman suit and had his hands to the window Mr Chapman was not formally interviewed by police until six months after William Tyrrell went missing

Giving evidence before the inquest, Ronald Chapman said he thought a delivery driver had arrived with his plant cuttings when he heard a loud noise on the morning of September 12, 2014 — the day William was reported missing.

When the Laurel Street resident went outside, he said he saw a boy "about three or four years old" being driven away from Benaroon Drive in a "fawn-coloured four-wheel drive".

"In the backseat was a young boy with his hands up on the window [facing] outwards on the glass of the window," he said.

"He was standing and unrestrained. He wasn't crying. He was wearing a Spider-Man suit.

"I definitely saw William. I am 100 per cent certain it was William in the back of the car … no doubt."

Mr Chapman was giving evidence before the NSW Coroner's Court in Western Sydney, in the fourth and likely final week of the inquest into the William's disappearance.

The court has heard from a range of witnesses and experts to try to break open the case and find a long-awaited new lead.

Mr Chapman said he was certain he saw William in his Spider-Man suit. ( Supplied: NSW Police )

In his evidence, Mr Chapman, a retiree, described the driver he saw as a woman "in her late 20s or early 30s" with blonde hair "tied up".

"She was driving with speed," he said.

"I couldn't estimate how fast [but she] almost lost control as she came around the corner."

Mr Chapman told the inquest he saw a blue sedan close behind driven by a man, which was also travelling quickly, but on the wrong side of the road.

"He had virtually two wheels on the grass as he came around the corner on the wrong side of the road," he said.

Police raking through bushland in Kendall last year in the search for new evidence. ( ABC News: Mark Reddie )

That night, Mr Chapman turned on the television to watch the news and heard a boy last seen wearing a Spider-Man suit was missing from the local area.

When asked why he did not alert police about the potential sighting until weeks later, Mr Chapman said he was waiting for police to come and interview him.

"The detective in charge made several announcements on TV that they were going to come and interview people within a 1-kilometre radius," he said.

"I was waiting for a knock on the door … it was several weeks later.

"In hindsight I should have gone sooner … you have second thoughts, I suppose I anguished a bit going forward."

Weeks later, Mr Chapman said he approached the sister of a local police officer at the Kendall Services Club and told her to pass on the message about what he saw.

But the inquest heard Mr Chapman was not formally interviewed by detectives for six months.

Detective Sergeant Laura Beacroft previously described Mr Chapman as a "credible" and "well-respected man" from the Kendall area.

It is yet to reveal what happened to the boy.