The unknown man is described as being aged in his mid-to-late-20s, and wearing black tracksuit pants, a grey hoodie, a black jacket, a black cap and red Nike reflective shoes.
Witnesses reported the man running from the scene of the accident. Police began a search of the area soon after.
At about 6:00pm on Monday, police received a report of a man matching his description on Brindabella Road, about three kilometres west of Uriarra Village, but police could not find him.
Police have continued searching for the man across Monday and Tuesday, and although some items believed to have been in the man’s possession have been located, he has not.
There are concerns for his welfare as he may have sustained injuries in the accident.
Police are asking anyone who may have seen the man, or interacted with him to call 131 444 to help police locate him and check on his welfare.
Anyone in the search area is asked to keep a lookout for the man, and to be aware of Search and Rescue personnel who are working in the region.