Point Hut human remains may be those of man who went missing in December

Detective Superintendent Hall O'Meagher, the head of the ACT's criminal investigations, said the identity and cause of death of the deceased male found in the long grass about 150 metres off Point Hut Crossing Road would not be determined until the results of a post-mortem examination later this week.

Two people walking in the area on Sunday afternoon made the grisly discovery.

"Obviously it was a shock and surprise for them," Supt O'Meagher said.

Police described the area where the body was found as heavily overgrown, with tall grass more than a metre high and thick blackberry bushes.

It is at the northern end of the crossing near to the Murrumbidgee River.

The body was found and reported about 3.45pm on Sunday and police immediately sealed off the area. Point Hut Crossing Rd has been closed off to the public and a series of cordons have been established around the area.

Tim Lyons was reported missing around 4pm on December 19 last year. He was last seen at his home in Gordon.

Police had made several appeals for information about his whereabouts and spent weeks conducting extensive searches in Tuggeranong before they released pictures and spoke to the media on January 10.

At the time of his disappearance, Detective Acting Inspector Emma Quade said Mr Lyons' disappearance was "extremely out of character for him".

He had no known access to a vehicle and was not known to frequent the Point Hut Crossing area, so homicide detectives have joined the investigation and will be adding their knowledge and expertise.

Police have been in contact with the Lyons family and familial DNA has been collected which will add certainty to a potential forensic "match".

Mr Lyons did not have a digital "footprint", which has made it very difficult for him to be found.

Police believed Mr Lyons may have been carrying an orange tiger-patterned blanket and a blue and red crotchet rug when he left his house.

Police would not confirm whether these crucial pieces of identifying material were found at the location, only that "some items" were found with the body.

Experienced forensic investigators have already judged the remains to be several months old, which would rule out the male being one of the ACT's long-term missing people.

Forensic processing of the site continued on Monday and consideration is being given to conducting a broader line search of the area, in case other items of evidence had been scattered.

Police describe it as a "open and active" investigation and are appealing for anyone who was in the area of Point Hut Crossing in the past few months and can assist the investigation to contact them via Crime Stoppers on 1800 333 000.