Labour called on the Government today to stop train companies raising fares above strict limits.
From tomorrow, regulated fares, which include season tickets, will rise by an average of 6%.
But under existing "flexible" rules, operators can - and are - putting up some fares by more than this as long as all their regulated fare rises do not exceed the average 6%.
In the last year of the Labour government, the then transport secretary Lord Adonis scrapped this flexible rule, telling train companies that no fare could go above the set limit for that year.
But the present Government has gone back to the old regulation, which means that some season tickets are going up by as much 10.6%.
Under Labour's plan, no regulated fare could rise tomorrow by more than 6%.
Labour is also concerned that, with fares set to rise by an average of RPI plus 3% for January 2013 and for January 2014, some commuters could be paying as much as 13% more for their season tickets in the future.
Shadow transport secretary Maria Eagle said today: "Life is already tough enough for families and commuters struggling with the increasing cost of living.
"But many commuters are in for an unwelcome new year surprise this week when they discover that the price of their rail ticket has risen by much more than (Chancellor) George Osborne promised."
She went on: "Instead of price rises being limited to 1% above inflation, some of the most popular commuter routes will see the cost of a season ticket soar by hundreds of pounds.
"This is a direct consequence of the Tory-led Government caving in to pressures from lobbyists and deciding to side with the train operators.
"It shows how utterly out of touch the Tories are with the impact of spiralling commuting costs on household budgets. Under Ed Miliband, Labour will take on powerful vested interests and stand up for commuters against this sort of predatory exploitation."
Measures to stop excessive fare increases are expected to be a key component of Labour's rail policy review.