Steven Groat, 54, from Wyoming, north of Gosford, was last seen on December 19 when he left a friend's house in Orange.

His car, a blue Holden Commodore, was found in the forest on Christmas Eve.

A resident of Cadia Road in Springside called police about 4pm on Sunday to say he believed he had located a body.

The corpse was found about 50 metres inside the forest, police said.

Although the body has not yet been formally identified, it is believed to be that of Mr Groat, police said.

Family members raised the alarm on December 23, advising police Mr Groat's lack of contact was unusual. There was also concern he was without medication,.

"This is completely out of character for my Dad to not have been in contact with any of our family or friends for this amount of time, especially this close to Christmas!" his son Mitchell Sutherland posted on Facebook. "We are extremely worried."

On the night of January 4, an anonymous phone call was made to Crime Stoppers, with the caller providing information about Mr Groat's possible whereabouts, the Western Advocate reported.

Last week, his daughter Kristie pleaded for help as police - including dog units and the PolAir helicopter - continued to search the forest.

"Since our dad Steven Groat was last seen, the past 19 days has been a blur and unbearable to say the least," she said. 

"Having to go through the holiday season has been extremely difficult and trying to explain to our children where their Poppy is has been one of the hardest parts. No family should have to endure this."

Following the discovery of the body, a post-mortem examination will be conducted and a report prepared for the coroner, police said.

On Sunday night, Mr Groat's son Mitchell Sutherland changed his Facebook profile picture to an image of himself with his father, and was flooded with supportive messages from friends.