Some of the public transport fare rises starting next week are "exorbitant", a passenger groups has said.
From 2 January, many main line fares are set to rise by 4.3%, with Tube users also facing increased fares.
London mayor Ken Livingstone said passengers using the Oyster card would find fares had been frozen.
But Brian Cooke, chairman of passenger watchdog body London TravelWatch, said non-Oyster card users were being penalised by too high fare increases.
Oyster fares that have not risen in price include a single journey on the Tube, which is still £1.50, and peak-time bus fares, which remain at £1.
But an annual Oyster card season ticket for travel in all six Underground zones will rise 4.88% to £1,720 when the fare changes come into force.
Mr Cooke said: "We are extremely concerned about the exorbitant cash fares on both buses, which rise by a third to £2, and on Tubes in Zone 1 (in central London), which passengers will see rise to an astronomical £4 - even if only going one stop.
"This will especially hit infrequent visitors and tourists to London, who will not necessarily benefit from the cheaper prices available when using Oyster cards.
"These fare increases could drive people away from public transport back to cars and taxis, which would be deeply disappointing."
Mr Cooke said there was also disappointment that London train users were facing fare increases when they were already facing overcrowded trains and crowded station platforms.
"We are especially concerned about the big rises in longer-distance journeys in and out of the capital. A longer-distance journey that cannot be planned well in advance is now becoming prohibitively expensive," Mr Cooke said.
Mr Livingstone said: "There are now huge savings to be made by using Oyster. We have been able to freeze many Oyster pay-as-you-go bus and Tube fares this year. Many now cost half the same journey paid by cash.
"We said that in order to pay for massive investment in our public transport system, including new rail links and better services, there would be three years of 10% fares increases.
"The savings and efficiencies made by Transport for London mean that the planned 10% increase in fares for this year has been cut back."