They have armed themselves with shovels and spent hours digging at possible burial sites, lobbied for a $250,000 reward in Matthew Leveson's case and come face to face with the man once charged with killing him.

All of it has been in pursuit of the ultimate end goal - to find "Matty" and bring him home.

That time may finally have come after a search in dense bushland south of Sydney uncovered a human skeleton on Wednesday afternoon.

An excavator running over the soil in the Royal National Park came to a sudden halt about 2.30pm after the driver spotted the bones.

The officer-in-charge of the case, Detective Chief Inspector Gary Jubelin, was called over before Mr and Mrs Leveson, who had been at the search site every morning for the past week, were ushered over.

Within seconds, the detectives and Matthew's parents were embracing and sobs echoed throughout the forest.

By nightfall, forensic officers in white suits were huddled over the bones with torchlights.

As the officers worked, Mr and Mrs Leveson said they hoped they would finally be able to lay their son to rest.

"It's been nine years, eight months and eight days," Mrs Leveson said. "We made a promise and we kept it, and now we can lay him to rest if it turns out to be Matt - and our boys won't have to go though their lives looking for their brother."

Mrs Leveson said her son's ex-boyfriend Michael Atkins, who directed police to dig in the Royal National Park, could have ended the family's pain nine years ago.

"He could have ended this and he chose not to," she said through tears. "He chose to stay in Queensland and not come down. He could have been down here helping, but no, he didn't."

The bones will now be forensically examined to establish whom they belong to. In a press conference on Wednesday night, Chief Inspector Jubelin said the remains were "consistent" with being those of Matthew.

"The human remains have not been confirmed as Matthew Leveson but they are consistent with being Matthew Leveson's remains," he said.

"As sad as it is, there is relief for the family ... they can bring their son home."

It was the third time in six months the area, not far from Waterfall train station, had been searched.

Wednesday's operation was moments from wrapping up when the skeletal remains were uncovered 100 metres from McKell Avenue.

It marked an extremely emotional and bittersweet moment in the long-running case that took a sensational turn late last year.

An inquest into the 20-year-old's disappearance came to a dramatic adjournment last November after Mr Atkins provided police with crucial information.

The 53-year-old was the last person seen with Matt alive - leaving ARQ Nightclub in Darlinghurst in September, 2007. He was charged with murder, but was acquitted in 2009.

In a rare move, Mr Atkins was granted immunity from prosecution last year to give evidence at the coronial inquest.

That meant his testimony could not be used against him in any future criminal proceedings. However, it didn't protect him from being charged with perjury or contempt of court.

In a final bid to recover Matthew's body, his parents agreed to the NSW Attorney-General offering Mr Atkins a second olive branch.

He was given immunity from perjury charges if he showed police where Matthew's body was.

Mr Atkins, who now lives in Brisbane, told police Matthew's remains were just off a bend in the road, not far from a bushwalking track.

Detectives spent days searching the site in November but found nothing. They returned to the area in January, focusing on a site 500 metres down the road, but again came away empty handed.

The most recent search was seen as a last-ditch attempt, an accuracy-focused exercise to make sure they left no leaf unturned before the inquest resumed in August.

"It is dotting our i's and crossing our t's and double checking, " Mr Leveson told Fairfax Media last week. "The long-term plan, and it always has been, is that we are not giving up."

The coroner, Elaine Truscott, and a forensic pathologist were expected to arrive at the crime scene on Wednesday night.

In a statement, police said an anthropologist would also examine the remains, which may be further analysed with DNA testing.

Police will return to the scene on Thursday morning.???