The body was found about 500 metres southbound from the Cotter Road overpass of the parkway.

The circumstances of the missing man's death are unknown and police will be seeking to determine the cause of death from the forthcoming post mortem.

A bushwalker found the body late on Friday morning and reported it to police, who immediately shut down the southbound lanes of the parkway and redirected traffic up the Cotter Road ramp.

Mr Watson suddenly disappeared from his Bonython home on March 31. He had left food on his dining table and hadn't accessed his bank accounts or phone since then.

Family grew concerned over a number of weeks when they hadn't heard from him. This was unusual because he would usually be in regular contact, police said.

After barriers were put in place to protect the scene, a line search was conducted of the area late on Friday afternoon.

ACT crime detectives were managing the scene and the case.

The head of the crime team, Superintendent Hall O'Meagher said that any members of the public who had any further information which could assist the investigation was encouraged to call Crime Stoppers.

"The examination of the scene is ongoing," he said.

"It will include a physical search of the area and obviously we are hoping to find items of relevance to the investigation.

"We have our forensics officers at the scene but it's apparent from early observations that this person has been in situ at the location for some time."

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