The Transport Minister, Norman Baker has launched a consultation on ideas for dealing with congestion on the transport system.
In an interview with the Guardian newspaper he is reported to have warned of the need to fast-track changes to the rush hour because of the Olympics, warning that it would be "impossible" for the capital to accommodate the visitors anticipated for the games as well as going about its business as usual.
Jenny Jones said: "The big fear is that this idea of staggered fares will translate into higher fares at peak times, not lower fares for off peak.
"The London Assembly has had numerous reassurances from Olympic officials and the mayor that London can deal with the extra traffic, so it comes as a surprise to find a Minister apparently saying it will be impossible for London to cope."