Concern about rail ticket prices and bus driver behaviour contributed to a 15% rise in complaints made to a London passenger watchdog.
Rail fare increases prompted many of the 1,748 complaints
Of 1,748 complaints dealt with by London TravelWatch in the past year, rail fare increases and ticket restrictions prompted most concern.
Chairman Brian Cooke said staff conduct on buses "continues to be a problem".
An Association of Train Operating Companies spokesman said many "cheap" rail tickets were available in advance.
Standards of driving
But Mr Cooke said rail passengers remain concerned about getting value for money from their tickets.
"The large premiums that train companies in the London area are now paying the government for the franchise is a cause for concern," he said.
"These premiums are much larger in the London area, where over 70% of all national rail journeys take place. Londoners are getting fed up with effectively paying more for their tickets, and subsidising loss-making lines elsewhere."
London TravelWatch received 52 complaints about bus driver behaviour, and standards of driving on London buses also prompted a number of complaints.
A Transport for London spokeswoman said: "London's buses operate in one of the most challenging urban environments in Europe.
"London bus drivers receive more training than drivers anywhere else in the UK, and driving standards are monitored closely through an extensive programme of 'mystery shopper' style observations carried out by instructors from the Driving Standards Authority."
She added that around three billion journeys were made on Transport for London's network in the past year, "so the number of complaints to London TravelWatch which relate to this network - just 680 in total - is a tiny proportion".
The Association of Train Operating Companies, which represents all UK rail operators, said there were no plans to reduce rail fares nationally.
"Some fares are perceived as expensive, while some advance purchase fares are ridiculously cheap," the spokesman said.
"Compared to the cost of coach, bus and air travel, train fares remain extremely competitive."