A 33-year-old man who has not been seen for six days was only reported as missing on Monday, ACT Policing said.
John Catlin has not been seen or heard from since 15 November.
"He was last seen at Gundagai, NSW, and is understood to have boarded a bus heading to Canberra," ACT Policing said.
He is Caucasian was a medium build and dark hair. When last seen, he was wearing green shorts and carrying a black backpack.
Police said his family are concerned for Mr Catlin's welfare and are requesting the public's assistance in locating him.
"Anyone who may have any information that could assist police in locating John is urged to contact ACT Policing Communications on 131 444 from within the ACT, from elsewhere in Australia please call 02 5127 0051," they said.
"Please quote reference number 7276972."