Rail fare rises mean some commuters will have to pay more than £5,000 for season tickets from Sunday, the Campaign for Better Transport (CBT) said.
This total is about 20% of the average UK salary and is the equivalent of Transport Secretary Philip Hammond paying more than £27,000 for a season ticket, the CBT added.
Backed by TV presenter and actor Michael Palin, the CBT will next week launch a campaign entitled Fair Fares Now to coincide with the return to work of travellers after the festive break.
Season ticket holders face average rises of 5.8%, with some Kent commuters having to fork out for increases of almost 13%.
CBT chief executive Stephen Joseph said: "Commuters feel like they are being pick-pocketed by the Government, expected to pay more year on year for the same poor quality service. Even with the promised extra investment, many passengers will see no actual improvement to their daily commute.
"Politicians need to start living in the real world and understand that people simply cannot afford to pay a fifth of their income just to do a day's work. The Government pledged to create fair fares and we all expect them to keep that promise."
The CBT said higher fares were pricing people off the train, which risked reducing access to work in London and other major UK cities. Forcing people back on to the roads would also generate more congestion and increase carbon emissions.
Michael Palin said: "Rail fare rises are holding travellers to ransom and increasing the likelihood that people will have to take to our already-overcrowded roads. Regular price hikes are no way for the Government and train companies to reward their regular customers.
"Instead of milking them, they should be thanking them for their loyalty with a better, simpler, more competitive fare structure."