Kylie Spelde said her family first heard on Monday evening that a jaw bone had been found at Perthville, just a few kilometres from where Ms Vaughan was living in Rocket Street at the time of her disappearance in 2001.

National news coverage of the find initially linked it back to Ms Vaughan's case, and the family thought their worst fears may at last be confirmed.

It took less than 24 hours for early forensic examination by an anthropologist to determined the remains were ancient, and most likely those of an indigenous person, but it was an agonising overnight wait for Ms Vaughan's family until that news was made public.

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Mrs Spelde said her family desperately wants to know what happened to Ms Vaughan - who vanished after getting into a small red car in the early hours of December 7, 2001 in Keppel Street - but the reality of thinking that jaw bone could have been hers was gut-wrenching.

"It was just a really awful night," Mrs Spelde.

"We were just going away on holidays with the kids when I got the phone call. My heart just dropped. It's been a really bad night.

"Everything just shuts down, it's so close to home."

Mrs Spelde said even news on Monday morning that human remains had been found at two Port Macquarie beaches, more than 500 kilometres from Bathurst, immediately got her family worried.

"Because we don't know where her murderer is the bones could be anywhere," she said.

"Look at the bodies in the suitcase case, the remains were 2000km apart."

Mrs Spelde said she was surprised information about the bone discovery got out so quickly and after it was linked to Ms Vaughan's case in the national media, she quickly called her elderly father so he wouldn't hear the news from a stranger.

"It's so heart-breaking. We really want [to know what happened] but now it is here, it's just so hard," she said.

"As a family we all rallied around on Monday night and talked it through with each other. It was good in that sense but it's so awful. The pain, it's agonising."

The jaw bone at Perthville was found by a man out walking alongside levee banks currently under construction by Bathurst Regional Council.