Vasile Belea was separated from his son at Victoria on Tuesday at around 10am, when the tube doors closed as he was left behind on the platform.
Vasile was visiting his son for Christmas, and is due to go home at the end of this week.
Investigating police believe he may have boarded the next train or attempted to get the train back to Hackbridge in Sutton where his son lives.
PC Richard Owen, from Sutton’s Missing Persons Unit, who is leading the investigation, has voiced his concern as Vasile speaks limited English.
‘He is described as 6ft tall with grey hair. He was wearing blue jeans, a long dark black jacket and a black flat cap,’ said a police spokesman.
‘He has money and an Oyster card. He has an iPhone but no SIM card so cannot be contacted.’
Anyone who sees Mr Belea is asked to call 999 or the Missing People charity on 116 000.