The partially decomposed body of a man was found on Saturday by bushwalkers and their dog in an almost inaccessible part of the mountain range near Freemans Waterhole.

Crime scene experts spent two days at the grave site before the remains were completely exhumed yesterday afternoon and taken away for an autopsy, expected to be conducted today.

The condition of the remains made it impossible for any positive identification at the grave site, although detectives were looking at recent missing persons' cases as they attempted to put a name to the body.

Those cases include the suspicious disappearance of Cardiff man Jay Riley, who has not been seen since leaving his Crockett Street house on December 14.

The 27-year-old has not touched bank accounts and his blue 1991 Toyota Lexcen remains missing.

However, the area's proximity to the F3 Freeway, the Central Coast and the coalfields could allow a killer to use the dense bushland as their dumping ground.

Lake Macquarie detectives, who have been joined by Sydney-based homicide squad investigators, are hopeful forensic pathologists may be able to formally identify the remains today.

The fact that the remains were only partially decomposed has ruled out any link with the disappearance of convicted bank robber Nathan Kain.

Kain is believed to have been murdered and his remains dumped in the Watagans not long after he left a Cardiff house with the intention of driving to the Central Coast in July 2006.

How long the remains have been in the bush grave may be difficult to determine.

Many variables, including temperature, rainfall and the amount of direct light received in the area all contribute to the rate of decomposition.

The Herald understands that the area where the grave was found was extremely remote and wet from recent rain.

Lake Macquarie local area commander Superintendent Craig Rae said police had remained tight-lipped about the discovery for operational reasons.

He said that it was still too early to speculate on any link with local missing persons' cases.