A man has been charged with an alleged one-punch attack on his father in Brisbane's CBD that left the older man in an induced coma in hospital overnight.

Gold Coast man Mark English, 53, was walking along Ann Street opposite Central train station with his partner, Varri Telfer, about 4pm Monday, when his son spotted them and allegedly attacked.

Paramedics treat a man apparently coward punched on Ann Street in the Brisbane CBD. Credit:Jorge Branco

Police said the 25-year-old Teneriffe man had a "brief verbal exchange" with the couple before punching his dad in the mouth.

Mr English fell backwards and was knocked out when his head hit the concrete.